I've had a bit of trouble as of late with getting paid off when I make my sets on the flop. Of course the guy(s) I'm in the pot with have to have some sort of hand, but say I hit my set on the flop and are first to act - should I come out firing, or try entice someone else to be the aggressor?

If I'm raised into with a substantial bet by the pf raiser, and I am the only other person in the flop. Should I generally flat call, then re-raise the turn. Or re-raise the flop? I just feel that I'm giving away the strength of my hand at the wrong times, and I'm not stacking anyone or getting paid off the amount I really should be.