Any action is mastered only through application, of course, but you have to first be aware of the action. If you don't know about, say, the technique of saying <- LEFT <- or -> RIGHT -> in teamchat for flags, or the best way to protect a flag-bearer, you won't be able to do it. Whether you learn about the technique by reading a post or seeing it happen in game leads to the same theoretical knowledge of it, which is separate from its application and mastery. Reading is never enough, but it can be a good start.
Not that this thread is really meant to be helpful.
Not that this thread is really meant to be helpful.