Here's a few guidelines on starting hands and how to play them, condensed from "Sit 'n Go Strategy" by Collin Moshman.
Premium hands: AA, KK, QQ: Raise/re-raise large preflop to get value and to get rid of people playing trash. For QQ, if you are at an aggressive table with a lot of raising pre-flop, you can limp QQ if you are in early position and re-raise a raiser. Be prepared to throw QQ away post-flop if there is an Ace or King on the board and a lot of action. Same for KK if there is an Ace on the board, if you've been aggressive and people are calling your bets it's a very strong possibility that they now have a pair of Aces post-flop, in which case you're a longshot to win the hand.
AK: In late position, raise 3BB plus a little more for each limper in earlier position. If somebody has already raised earlier, just call. Be prepared to toss AK post-flop because it's nothing more than a drawing hand and while it has good value pre-flop, it's garbage if it doesn't connect with the board. Bet for value if the board has A or K, bet higher to price out potential draws if they exist. Moshman states that if there is a raise from early position and several callers making for a big pot, you can consider shoving from late position to try and win the hand without seeing a flop at all.
AQ, AJ, JJ, TT, 99: In early position, tend to fold AQo, AJ. Limp or make a standard raise with AQs, TT, 99, raise with JJ. In middle or late position, call or raise with all these but tend to fold AQo and 99 if somebody has already raised to keep from getting out-flopped and losing all your chips.
Speculative hands: Suited/high semi-suited connectors, suited Aces, low to mid pocket pairs: You want to be in middle or late position, and limp into an unraised pot that already has at least 2 limpers. The goal is to see a flop as cheaply as possible, therefore you should not call to enter pots where somebody has already raised. If you think there's a good chance that a short stack in the blinds will shove, fold and save your chips.
These are general guidelines to start out with and aren't set in stone, like so many other things in poker it depends on the specific situation that you're in. Be careful with playing hands like A6, A7, A8, if you raise with these and somebody calls there is a good chance they will have a better Ace and if there is an Ace on the flop you will wind up losing all your chips.