You say you "overbet" ....how 'bout an example. Do you bet 3x the BB or more?
If I flop a set...and there is a straight or flush draw out there I generally fire out a good sized bet (3xBB) to find out where I am and to make the drawers pay. If they fold...I am happy to take the bets already out there....but making it pretty cheap for them to draw on you, just to get an extra bet or two sounds like a recipe for disaster.