What I've learned from books and playing is that it's vital that you be able to win a HUGE pot if you hit your hand. In position with small connectors (suited or not) I've called 2x or 3x bb bets from players I was sure had AA or KK in hopes of busting them.

One hand I remember I had

8 9

and called a decent raise from a big stack. Flop came

Q 10 7

He bet and I pushed all in (we're about even money at that point). Of course he called and I took it down when my flush hit.

Basically in NL you have one goal: to get your opponent's stack. The game is to figure out how. Some players can't release AK when it doesn't hit after the flop. Others can't release big pairs. Others chase weak flush draws. Get them into positions where you're getting the right odds based on their stack size and you can't go broke. Make them chase you.