Great Cards
If you have AA, KK, QQ those are monstor cards. They are probably the best hand at the table, and you can play them from any position. You can even play them after someone has raised. In fact, they are that good that you should raise with them, or re-raise if you have the chance. Things are looking up for you.

Hands like AK, and AQ are also great cards. Raise with them because they're a great starting hand. If someone already raised, call their raise. After all, you've got some great cards.

Any of those hands play better against one or two opponents than they do against a large field of players. So, before the flop you'd like to thin the field to just one or two other players. That's part of why you raise with these hands. You want to chase all but one other player out of the pot.

Very Good Cards
Then there are the good cards, like AJ, AT, KQ, KJ, QJ. Since there are so many other better hands out there, you really only want to play these if seeing the flop is cheap. If you're in early position, take a pass, because someone may raise behind you making this a bad hand to have if you have to pay two bets to see the flop. If you're in middle position, well, play them if it looks like you can see the flop for one bet.

Pocket Pairs
These are a potential trouble spot. The problem with pocket pairs is that they look so damned good that they are hard to let go of later in the hand. But, if you can get away from that tendency, there are some riches to be had with pocket pairs.

While top pairs like AA, KK, and QQ deserve raises and re-raises if you can get them in before the flop, other pairs you have to play differently.

If you have a middle pair, say JJ, TT, or 99, there are two ways you are likely to win the pot. Either flop your set, or have an "overpair" (a pair higher than any of the cards on the board). I like to see flops with these cards, so I play them from nearly any position.

The rest of the pocket pairs pretty much need to turn into a set to win a pot. But, when they do turn into a set, they are a good hand that is well disguised. The problem with having to land a set . . . it only happens one time in 8 flops, give or take. So when it happens, you need to win a big pot to make it worth taking the chance of playing these cards.

So, play those hands for cheap against either a lot of players, or a few players that will bet and bet like crazy. Either way, you only want to play these cards in hands where the pots will grow into big ones.