Swiss ball crunches - make sure that you lean back far enough to where you feel like you might roll over backwards. 3 sets of 15 each Swiss ball oblique crunches 3 sets of 15 each Roman chair leg raises (for lower abs) 3 sets of 10 (or more if you can do them) I also recommend that you practice "vacuums". On your hands and knees, blow all of your air out, then suck in and see how close you can get your belly button to your backbone. Hold for 10 seconds. Do the same thing with the left arm and right leg extended. Then switch. Do this 3 times.

There's a saying that "abs are made in the kitchen". This is because it's a matter of getting extremely lean. Unfortunately on most people, the fat around their middle is the last to go. That is my case. I have a pooch on my lower belly unless I am at 12% bodyfat or lower. It's good to strengthen your abdominals on a regular basis because you are building and maintaining a strong muscle foundation there, but you can not target which fat cells will shrink. You will shrink all of your fat cells and hence your abdominal fat cells by having a strict nutrition plan and getting lean.