position preflop vs. after flop

[brimith]

I was recently told by a friend that I bluff too much preflop from out of position. I'm sure this is true. I have a hard time deciding how to treat a good-to-marginal hand preflop from, say, under the gun. Obviously I have the worst position to start off with, but in a six-player game, I'm not looking too bad after the flop. Should I more or less ignore the position change after the flop, and bet as if my position now is what it's going to be the entire hand? Any thoughts?