how do you play overpairs upon resistance? [with no reads]

EG you bet the pot or 3/4 at flop and get re-riased - I normally push all-in.

Obviously you want to be against TPTK or a drawing hand but I seem to be finding im up against 2pair or a set most of the time. I may adjust my play and start folding overpairs to flop re-raises (with JJ and below) but with QQ-AA i may be tempted to continue to push against big resistance.

Whats everyones ideas? I play $20nl 6 max