Portion control, make sure you are eating enough through the course of the day (5-6) to promote an active metabolism, Work on varying your abs routine to incorporate stability/ functional training, You actually burn calories longer when you weight train then when you do cardio although cario is very important so don't stop it, make sure you are training based on your AT (anaerobic threshold) learn you heart rate zones to do this properly, try to eliminate all high fructose corn syrup since that junk just sits on your belly (although this has not been proven 100% true, once I cut it out of my diet I saw significant results).
WORK WORK WORK
WORK WORK WORK