Someone should explain the difference between preflop and postflop aggression(this is for NL).


Preflop you need to be aggressive to cut down the field of opponents. It's hard for AA to hold up against the whole table calling. You want to bet enough so 1-2 people call only(and this amount varies by the game you sit in, sometimes allins get called by 3 people, sometimes a minraise gets called by no one).

Post flop, if you have what you think might be the best hand, you obviously want to make some money off it. You also don't want people drawing for cheap, so you make bets big enough to make their calls ev- for them.