buy css then install irc then go on aim maps and team death match for 2 weeks and also play dust2, inferno, train, and nuke on public then after 2-3 weeks depending on how good you are at fps games to to a league site and try join a low-mid team.
Once you have done this you will get to experiance the real game in 5v5 pcw, mixes and league matches.
Then game is amazing aslong as you have a fun and friendly team that want to improve