Something a good player said to me after saying he folded on the turn to my pot-sized bet on the turn on a Td 7c 2h Kd board (I had 79d and min raised the flop):

"What did you have? I had TA. Boy, you scare me. I just never know what you have."

Unpredictability is key in poker, especially NL. I would say it's the third most important "rule" or guideline (after "Play tight aggressive" and "Never tilt.")

Switch things up: make a stone cold bluff on 23o or 47o and show it when you take it down on the flop, raise suited connectors occasionally from EP and MP, do lots of semibluffing, sometimes limp-reraise big pocket pairs when you're first in the pot, set up a bluff on a later street with a min raise, etc..

Acting erratically makes it very hard for other players to read you, and is imperative to getting maximum value from your good hands. This is even more true in a live game, where people are paying more attention. Just make sure you don't overdo it, because that's when the odds turn against you and you start leaking away money.