Unless you have a good read on the hole cards your oppenent(s) are holding, I would not re-raise before the flop. Obviously the best strategy with small pairs is to call a small bet or limp in and then hit your set on the flop or see the turn cheaply and make it there. Hopefully the board will not have a lot of overs or a flush draw, and you can make it to the turn to see an extra card without fear of a higher pair allready having you beat. The odds of you hitting a set are about 7:1. So "theoretically" you shouldn't call before the flop unless the pot is allready built up or you believe that your opponet doesn't allready hold a higher pair.
This is bet played against two large overs, such as AQ or AJ. If you are lucky enough to have the flop come J-8-4 rainbow, with you holding pocket fours, you will have a very good chance of breaking him.This is because he has top pair with an Ace kicker and there is no way you would call a raise with J8. He will beat hard here, and you can come over the top of him violently
Playing small pairs is either feast or famine, as you will take down the occasional large pot, but many times will blank the flop. Just make sure you are seeing the flop cheaply so this is a move that will make money for you.