One of the clearest conceptual differences between limit and NL comes when you believe you hold the best hand and another player is pursuing a draw to beat you. As an example, suppose you hold:
and the flop comes
In both limit and NL, your TPTK figures to be the best hand, so you want to protect it. However, in limit, your only viable options are to bet or to try for a check-raise, depending largely on your position and your reads of your opponent[s]. It might be correct for you to bet and your opponent with:
to call. In NL, you can bet whatever you wish, and you can bet enough to make it incorrect for him to call.
Incorrect calls, not correct folds Edit
There's a difference between protecting one's hand and pushing one's opponents off their drawing hands. To do the former properly, you want to charge at least enough to give your opponent improper pot odds, but beyond that you want to maximize the expected value of their improper calls. You don't want to minimize the probability your opponent calls, or even to maximize the probability that you win the pot! (You're playing to win money, not pots.) You want to maximize your EV from improper calls.
Trying to push people off hands means raising enough to make them fold. If you do this every time you flop a good hand, you're sacrificing a ton of EV.
Granted, if the pot's very big you might be happy taking it down rather than allowing a marginally incorrect call. But most of the time, you want to bet the maximum that you think a draw might call (though never so little as to give right odds to call).
Discussion threads Edit
|PokerWiki's guide to playing no-limit hold 'em|