The more you learn and understand multiplayer the more fun it is. And the campaign is completely different so dont get all hyped up when you beat the last level on brutal, that you'll go diamond. I recommend watching videos on the challenges and doing those. Or this youtube guy my bro learned just about everything he knows about the game:
http://www.youtube.com/user/ForceSC2strategy
This is the first rts I ever got any good at, and it's intimidating at first, but theres tons of information on how to play online, WATCH the replays that you lose, or even if you win and it was close. The replay system is very useful. And watch the pros that play your race, I get these from sc2win.com personally.
http://sc2sig.com/s/us/1057610-1.png?1285272449
anyone want to play?