OK here's my two-penny worth and this is for what I call solitary play. i.e no voice comms with your team mates to coordinate your play.
CAMPING
Camping has it's place. Do it as needed and don't listen to people that whinge. They whinge, because it can be very effective in defeating them! Camping is very sensible indeed when you are defending your flag. It would be totally stupid to leave it undefended. Usually everyone's gung-ho and wants to attack anyway, but it would be good to always have one or two guys watching the base.
CTF
Before you rush an enemy base on CTF, check: 1) Is the flag there? 2)Is it full of enemies respawning? Pause a moment (in a safe place) and check the player list to see which of your enemies are dead/about to respawn or alive. If a batch suddenly die (names greyed out) you have at most only 5 seconds to get into the base and out with the flag. If they are all alive (names in white), chances are the base is empty (unless they are camping, which would be perfectly sensible since they have a flag to defend). You'll have to take them out in that case. Better to do this with one or two teammates, if possible. Prime a grenade before you rush and on two seconds release towards the first target you see. Head for the flag and take out your gun to use on secondary target. Try to follow the shortest entry>flag>exit route you can (with exceptions - see Ring a Roses, below). Once headed for the exit with the flag throw a second grenade in your wake to take out stragglers.
HUNTING THE FLAG
HTF is great fun. The sole objective in the game is to get the guy with the flag. Don't get bogged down in firefights with extraneous characters. Go for the guy with the flag - relentlessly! How many times have I see "xyz failed to score - own flag not taken"? Remember to make sure, always, that your own flag is taken before you victoriously leap onto the flag of your fallen enemy. It's the most anticlimactic moment in your life. Similarly, make sure the enemy flag has been taken before you storm the base - else you're wasting your time!
DEATHMATCH
Anything goes. This is the time for nade spam, and lots of it.
TOSOK
Everyone gets upset about camping in TOSOK, but in fact it's probably the most effective tactic, at least till you can shoot from the hip and use the sniper like a shotgun. Hint - you don't get a crosshair with the sniper unless you're scoping. You can make your own. Just get a tiny ball of paper and stick it to your monitor dead centre.
THE LIZARD SWITCH
I call it this because of the way lizards shed their tails when in danger. You are fleeing with the flag and you feel the hit of bullets on your back from an enemy in close pursuit. To continue to flee would usually be deadly. He's shooting you, obviously, but you can't even see him! The next corner you go around - stop, turn and wait. He will not be expecting you to jump out in his face when he turns the corner. Time it right and he will not be able to respond. Pump a round of pellets into him and he is done. Most effective with shotgun.
KNOW YOUR MAP
Critical. Every map has it's killing zones, pitfalls and nuances. Which team you play on will affect how to play each one too. In my experience some maps definitely favour one team or the other. For instance, Complex is heavily in favour of red team. Play every map to your maximum advantage. Too many to go into here but this will come with experience. An obvious example is in mines. It is a bad idea for CLA to assault up the steep ladder on the left side of the map since it takes them through an exposed killing zone. It is however a great idea for RVSF to storm down that way.
RING A ROSES
There's a maxim in warfare - Be where your enemy does not expect you. This is true just as much in AC. Like it or not, every player plays according to a set of preconceptions of what he expects his enemy will do and where he will be. And this is because usually he is right. Usually. But if you don't conform, he won't be able to cope and you've got him. The ring a roses is a beauty. It goes like this. You are evading an enemy (with the flag, say in his base) and he is tracking you. You run behind an obstacle (say a wall in Shine) and as far as he can tell you are running in a straight line, so he aims up his sights on the end of that obstacle to wait for you to come out (calculating absolutely perfectly your trajectory from your speed and direction). You are dead meat in this case. But wait. Don't do it. As soon as you are out of sight behind that obstacle, stop - go back the other way and get behind him, or do something TOTALLY RANDOM.... He'll be totally confused. Be where your enemy does not expect you. Take this principle to any extreme you want. It works.
TAKE COVER
At every moment you should expose yourself as little as possible. The one time you can't do this is in the enemy base when going after a flag. Otherwise, use passages, tunnels, underpasses, alleyways and doorways to cover yourself. Don't go through the big open areas, they are usually killing zones. Wherever possible have walls on two sides of you. The more exposed you are the more likely you are to die.
KEEP MOVING
Unless you are camped in a safe spot, keep moving! Staying still, especially in an exposed position usually gets you killed within 3 seconds. A moving target is a hard target.
IN THE SOUP
Water is a mixed blessing. It can give you great cover, but mostly it just slows you right down till you're literally a sitting duck. Avoid, unless you really are hiding from someone. Beware grenades in water. They don't go very far and tend to blow you up! Funnily enough guns seems to be effective as normal.
STRAFE RUN
Strafe running, or running on the diagonal is quicker, due to a geometrical nuance of the game architecture it's just the way it is. Do it, since the faster you go the harder you are to hit and the quicker you can get the flag.
ARMOR
Is armor worth the trouble? Armor gives you a tactical advantage in a firefight, so yes, it most definitely is! Is it worth waiting 20 seconds on the armor spawn to get it? Probably not. Always try to get it when you are in a position to. It's a really good idea to get some armor at the beginning of a round as your chances of surviving those intial encounters will be about 100% greater. Then, replenish it. You can literally get through a heap of enemies this way (providing your encounters are one v one). I reckon armour about doubles your chances of escaping the enemy base with the flag.
HEALTH
Healthpacks recycle much faster than armor and are just as critical. No point storming the enemy base with 4hp. You could get away with it, but chances are you'll be going straight back to the beginning. There are loads of healthpacks strewn across every map. Know where they are and make full use of them. Even in a firefight with enemies jumping like kangaroos all around you, try to maneouvre yourself over the health packs and increase your chances of surviving.
RELOADING
At some point you are going to have to do it. The time to do it is a quiet moment before an encounter, not in the middle of a frenzied gun battle over the flag! Keep an eye on the ammo levels and reload regularly, literally whenever you have the chance. Never go into a firefight without a full magazine and one in the chamber.
MAKING A STAND
I know I'm not alone in this little tactic. Find a part of the map close to healthpacks, nades, armor and ammo and then make it your territory. Literally any enemy who strays into that patch is gonna die from now on, and you are going to patrol it and constantly replenish yourself to full armor and health as you need. You can really boost your frags doing this.
DUCK AND COVER
There are loads of objects to give you cover in most maps. Use them to your advantage. For instance the big boxes cover most of your body, leaving head and shoulders exposed. If you use them your enemy has only a small target to aim for. Admittedly he might be a sniper and only interested in your head anyway but you will have all of him to aim for and he doesn't. If you're using a shotgun duck between shots as you cock the gun and get up to shoot again. That way he has less time to shoot you too. In the same way there are higher obstacles and windows too that you can shoot through by jumping. The wall at the top of the stairs near CLA base in power is a great example. Popping off a shot over a high obstacle can make a difference, and you can do it with impunity.
THE NADE PUSH
This is not what I call 'spamming'. This is a progressive advance with nades clearing a path in front of you. You can do it on most maps, although Power and Depot are obvious examples. Get your first nades. Leave base and head for the enemy, launch your first nade at a critical junction (doorway/route/crossing whatever). Launch your second nade at the next critical junction, or at the next nade spawn. Run to the next nade spawn and collect more nades. Launch again towards the next critical junction, and the second in time to get the third batch of nades. Attacking nade spawns is a good idea because you get enemy concentrations there. If you do this skilfully you should be able to avoid hurting friendlies and take out one or two enemies on your advance.
SITUATIONAL AWARENESS
Critical to any battle scenario, know where your friends are and know where your enemies are. The more information of this kind you have, the more advantage you have. Use the mini map if possible, to track friendlies and if possible move with them. This is a sneaky one, but following behind one or two of your teammates will reveal enemy positions to you and they will take the fire for you and might even take out the enemy. Great to sneak into enemy base behind a teammate this way. When you die you have a free look around you to see what's going on. This can reveal to you: who's camping where, where the guy with your flag is at etc. Use it.
ANTICIPATE
"xyz got your flag". Ok, a dude just got your flag. Remember that half the game is actually about defending your own flag. It's not just about capturing the enemy flag. Unless you have good teamwork going on and you can divide the labour this might be a moment to think about where the guy is with your flag and take him out. Usually he has about three routes to go, so let's wait on one of them and see if he comes up. Chances are he'll be coming up and nailing you in the back anyway if you don't look behind you.
CROSSFIRE
Annoying getting TKed, and sometimes you're just holding back your fire cos your teammates are too close. You can exploit this. When confronted with a set of enemies, get in amongst them. This will screw them up as they'll be trying to avoid hitting each other, or they'll actually TK each other trying to get you! If you do this well you can take down a room full of enemies single-handedly (and with their help). It is literally hilarious to enter the fray with two or three enemies, kill one of them, but somehow you leave three dead bodies behind. No time to teabag...
HORSES FOR COURSES
I use the shotgun about 75% of the time. It's my favourite weapon. So why don't I use it 100% of the time? Well, TOSOK aside, because there are situations where it is no use. Certain maps, especially larger, more open maps are terrible for shotgunners because it is exclusively a short range weapon. Larger more open maps cry out for the SMG or the Sniper. Word of warning: The assault rifle is a useless weapon. It takes 15 rounds and has terrible recoil. Don't use it. It only has one advantage: rifle jumping. It's the only way to jump onto high ledges and get hidden on KTF, for example. It can be useful for running with the flag on CTF, but the SMG is actually better since it has 30 rounds and fast reload. I only use the AR on KTF. Sniper rifle can be deadly, and I'm always in awe of those guys who can take out a running player with a headshot, without using the sights (cheaters aside - you know who you are). I'm not that good with it so I don't use it much. Using the Sniper on little, chlaustrophobic maps is just hubris IMO and takes a lot of skill indeed. When shooting with the SMG start with a low aim. The gun will naturally rise with the recoil and pump a line of bullets all the way your enemy, sawing him in half.
TRY SOMETHING DIFFERENT
If you keep doing your usual thing and you get taken out on that corner every time by a headshot and your ratio's at 0.3 and you can't even get near the flag - it's time to try something different. Like anything in life, if what you're doing isn't working - stop doing it and try something else.
GAMESMANSHIP
Now this is a little Machiavellian to put this in, but you know what I mean. You can enter your enemy's psychology to defeat him too. How? You could try talking to him, just about anything really. Try to get him thinking about anything at all that isn't killing you and that's a good thing. Find out what really p****s him off and keep doing it, that's even better. Anything goes!
Nothing I mention can really compare to coordinated team tactics but that's the one thing you can't do on the pubs, so there it is. See you in game.
CAMPING
Camping has it's place. Do it as needed and don't listen to people that whinge. They whinge, because it can be very effective in defeating them! Camping is very sensible indeed when you are defending your flag. It would be totally stupid to leave it undefended. Usually everyone's gung-ho and wants to attack anyway, but it would be good to always have one or two guys watching the base.
CTF
Before you rush an enemy base on CTF, check: 1) Is the flag there? 2)Is it full of enemies respawning? Pause a moment (in a safe place) and check the player list to see which of your enemies are dead/about to respawn or alive. If a batch suddenly die (names greyed out) you have at most only 5 seconds to get into the base and out with the flag. If they are all alive (names in white), chances are the base is empty (unless they are camping, which would be perfectly sensible since they have a flag to defend). You'll have to take them out in that case. Better to do this with one or two teammates, if possible. Prime a grenade before you rush and on two seconds release towards the first target you see. Head for the flag and take out your gun to use on secondary target. Try to follow the shortest entry>flag>exit route you can (with exceptions - see Ring a Roses, below). Once headed for the exit with the flag throw a second grenade in your wake to take out stragglers.
HUNTING THE FLAG
HTF is great fun. The sole objective in the game is to get the guy with the flag. Don't get bogged down in firefights with extraneous characters. Go for the guy with the flag - relentlessly! How many times have I see "xyz failed to score - own flag not taken"? Remember to make sure, always, that your own flag is taken before you victoriously leap onto the flag of your fallen enemy. It's the most anticlimactic moment in your life. Similarly, make sure the enemy flag has been taken before you storm the base - else you're wasting your time!
DEATHMATCH
Anything goes. This is the time for nade spam, and lots of it.
TOSOK
Everyone gets upset about camping in TOSOK, but in fact it's probably the most effective tactic, at least till you can shoot from the hip and use the sniper like a shotgun. Hint - you don't get a crosshair with the sniper unless you're scoping. You can make your own. Just get a tiny ball of paper and stick it to your monitor dead centre.
THE LIZARD SWITCH
I call it this because of the way lizards shed their tails when in danger. You are fleeing with the flag and you feel the hit of bullets on your back from an enemy in close pursuit. To continue to flee would usually be deadly. He's shooting you, obviously, but you can't even see him! The next corner you go around - stop, turn and wait. He will not be expecting you to jump out in his face when he turns the corner. Time it right and he will not be able to respond. Pump a round of pellets into him and he is done. Most effective with shotgun.
KNOW YOUR MAP
Critical. Every map has it's killing zones, pitfalls and nuances. Which team you play on will affect how to play each one too. In my experience some maps definitely favour one team or the other. For instance, Complex is heavily in favour of red team. Play every map to your maximum advantage. Too many to go into here but this will come with experience. An obvious example is in mines. It is a bad idea for CLA to assault up the steep ladder on the left side of the map since it takes them through an exposed killing zone. It is however a great idea for RVSF to storm down that way.
RING A ROSES
There's a maxim in warfare - Be where your enemy does not expect you. This is true just as much in AC. Like it or not, every player plays according to a set of preconceptions of what he expects his enemy will do and where he will be. And this is because usually he is right. Usually. But if you don't conform, he won't be able to cope and you've got him. The ring a roses is a beauty. It goes like this. You are evading an enemy (with the flag, say in his base) and he is tracking you. You run behind an obstacle (say a wall in Shine) and as far as he can tell you are running in a straight line, so he aims up his sights on the end of that obstacle to wait for you to come out (calculating absolutely perfectly your trajectory from your speed and direction). You are dead meat in this case. But wait. Don't do it. As soon as you are out of sight behind that obstacle, stop - go back the other way and get behind him, or do something TOTALLY RANDOM.... He'll be totally confused. Be where your enemy does not expect you. Take this principle to any extreme you want. It works.
TAKE COVER
At every moment you should expose yourself as little as possible. The one time you can't do this is in the enemy base when going after a flag. Otherwise, use passages, tunnels, underpasses, alleyways and doorways to cover yourself. Don't go through the big open areas, they are usually killing zones. Wherever possible have walls on two sides of you. The more exposed you are the more likely you are to die.
KEEP MOVING
Unless you are camped in a safe spot, keep moving! Staying still, especially in an exposed position usually gets you killed within 3 seconds. A moving target is a hard target.
IN THE SOUP
Water is a mixed blessing. It can give you great cover, but mostly it just slows you right down till you're literally a sitting duck. Avoid, unless you really are hiding from someone. Beware grenades in water. They don't go very far and tend to blow you up! Funnily enough guns seems to be effective as normal.
STRAFE RUN
Strafe running, or running on the diagonal is quicker, due to a geometrical nuance of the game architecture it's just the way it is. Do it, since the faster you go the harder you are to hit and the quicker you can get the flag.
ARMOR
Is armor worth the trouble? Armor gives you a tactical advantage in a firefight, so yes, it most definitely is! Is it worth waiting 20 seconds on the armor spawn to get it? Probably not. Always try to get it when you are in a position to. It's a really good idea to get some armor at the beginning of a round as your chances of surviving those intial encounters will be about 100% greater. Then, replenish it. You can literally get through a heap of enemies this way (providing your encounters are one v one). I reckon armour about doubles your chances of escaping the enemy base with the flag.
HEALTH
Healthpacks recycle much faster than armor and are just as critical. No point storming the enemy base with 4hp. You could get away with it, but chances are you'll be going straight back to the beginning. There are loads of healthpacks strewn across every map. Know where they are and make full use of them. Even in a firefight with enemies jumping like kangaroos all around you, try to maneouvre yourself over the health packs and increase your chances of surviving.
RELOADING
At some point you are going to have to do it. The time to do it is a quiet moment before an encounter, not in the middle of a frenzied gun battle over the flag! Keep an eye on the ammo levels and reload regularly, literally whenever you have the chance. Never go into a firefight without a full magazine and one in the chamber.
MAKING A STAND
I know I'm not alone in this little tactic. Find a part of the map close to healthpacks, nades, armor and ammo and then make it your territory. Literally any enemy who strays into that patch is gonna die from now on, and you are going to patrol it and constantly replenish yourself to full armor and health as you need. You can really boost your frags doing this.
DUCK AND COVER
There are loads of objects to give you cover in most maps. Use them to your advantage. For instance the big boxes cover most of your body, leaving head and shoulders exposed. If you use them your enemy has only a small target to aim for. Admittedly he might be a sniper and only interested in your head anyway but you will have all of him to aim for and he doesn't. If you're using a shotgun duck between shots as you cock the gun and get up to shoot again. That way he has less time to shoot you too. In the same way there are higher obstacles and windows too that you can shoot through by jumping. The wall at the top of the stairs near CLA base in power is a great example. Popping off a shot over a high obstacle can make a difference, and you can do it with impunity.
THE NADE PUSH
This is not what I call 'spamming'. This is a progressive advance with nades clearing a path in front of you. You can do it on most maps, although Power and Depot are obvious examples. Get your first nades. Leave base and head for the enemy, launch your first nade at a critical junction (doorway/route/crossing whatever). Launch your second nade at the next critical junction, or at the next nade spawn. Run to the next nade spawn and collect more nades. Launch again towards the next critical junction, and the second in time to get the third batch of nades. Attacking nade spawns is a good idea because you get enemy concentrations there. If you do this skilfully you should be able to avoid hurting friendlies and take out one or two enemies on your advance.
SITUATIONAL AWARENESS
Critical to any battle scenario, know where your friends are and know where your enemies are. The more information of this kind you have, the more advantage you have. Use the mini map if possible, to track friendlies and if possible move with them. This is a sneaky one, but following behind one or two of your teammates will reveal enemy positions to you and they will take the fire for you and might even take out the enemy. Great to sneak into enemy base behind a teammate this way. When you die you have a free look around you to see what's going on. This can reveal to you: who's camping where, where the guy with your flag is at etc. Use it.
ANTICIPATE
"xyz got your flag". Ok, a dude just got your flag. Remember that half the game is actually about defending your own flag. It's not just about capturing the enemy flag. Unless you have good teamwork going on and you can divide the labour this might be a moment to think about where the guy is with your flag and take him out. Usually he has about three routes to go, so let's wait on one of them and see if he comes up. Chances are he'll be coming up and nailing you in the back anyway if you don't look behind you.
CROSSFIRE
Annoying getting TKed, and sometimes you're just holding back your fire cos your teammates are too close. You can exploit this. When confronted with a set of enemies, get in amongst them. This will screw them up as they'll be trying to avoid hitting each other, or they'll actually TK each other trying to get you! If you do this well you can take down a room full of enemies single-handedly (and with their help). It is literally hilarious to enter the fray with two or three enemies, kill one of them, but somehow you leave three dead bodies behind. No time to teabag...
HORSES FOR COURSES
I use the shotgun about 75% of the time. It's my favourite weapon. So why don't I use it 100% of the time? Well, TOSOK aside, because there are situations where it is no use. Certain maps, especially larger, more open maps are terrible for shotgunners because it is exclusively a short range weapon. Larger more open maps cry out for the SMG or the Sniper. Word of warning: The assault rifle is a useless weapon. It takes 15 rounds and has terrible recoil. Don't use it. It only has one advantage: rifle jumping. It's the only way to jump onto high ledges and get hidden on KTF, for example. It can be useful for running with the flag on CTF, but the SMG is actually better since it has 30 rounds and fast reload. I only use the AR on KTF. Sniper rifle can be deadly, and I'm always in awe of those guys who can take out a running player with a headshot, without using the sights (cheaters aside - you know who you are). I'm not that good with it so I don't use it much. Using the Sniper on little, chlaustrophobic maps is just hubris IMO and takes a lot of skill indeed. When shooting with the SMG start with a low aim. The gun will naturally rise with the recoil and pump a line of bullets all the way your enemy, sawing him in half.
TRY SOMETHING DIFFERENT
If you keep doing your usual thing and you get taken out on that corner every time by a headshot and your ratio's at 0.3 and you can't even get near the flag - it's time to try something different. Like anything in life, if what you're doing isn't working - stop doing it and try something else.
GAMESMANSHIP
Now this is a little Machiavellian to put this in, but you know what I mean. You can enter your enemy's psychology to defeat him too. How? You could try talking to him, just about anything really. Try to get him thinking about anything at all that isn't killing you and that's a good thing. Find out what really p****s him off and keep doing it, that's even better. Anything goes!
Nothing I mention can really compare to coordinated team tactics but that's the one thing you can't do on the pubs, so there it is. See you in game.