Try doing a range of abdominal exercises, including work for the lower abominals (reverse crunches) and obliques (like the Pilates criss-cross move). It is still best to combine with some regular cardio, since cardio and toning help each other to be more effective. I have found that Pilates is very effective in toning my entire body, particularly my torso and abs. I had a baby 2 months ago, and I can't wait to get rid of that nasty flab.