What are the best belly exercises to do?

What are the best belly exercises to do? I have a little extra flab around the middle. I would like to get rid of it and have defined abs. I have tried different exercises, but I didn’t really see results from doing them. There has to be a tummy exercise that works better than those I have already tried. I just have yet to find it. I don’t want to carry around a spare tire forever. I want to lose the belly fat and have sculptured abs. What do I have to do to see those results?