Best Starcraft 2 Strategy

[mightymap2]

What is the best Starcraft 2 strategy out there. I've been playing a while and can't seem to get very far in this game. It might be because I totally suck or I just don't have enough experience. I usually like to play the protoss race. Which race do you play and what's your preferred strategy?

 

[mightymap2]

Do you play the expansion or just the basic version of the game. Right now I play just the basic version of the game, Wings of Liberty. I haven't purchased the expansion though it is available and I've seen it advertised for about $20.