I'd say you should play on newbie servers at first until you know the basics of the game (what each class/weapon is like, the maps, base moving, etc). Then move to servers that don't have support too many players and that are frequented by good players (such as the Killaz server). That way you see good bases, base moves, strategies, and generally good players at work. And then to practice or try out what you learn, go back to the newbie servers.