Six pack. To flatten your belly you need to cut out carbs. No breads, beer, tropical fruits, etc. You also have to do aerobic exercise such as running, stair step, elliptical. Eat 5 meals a day, very important. I have a no carb protein drink between meals. This will allow you to eat less and helps your body maintain a more linear glucose level.
Lose weight. For flatter abdomen eat healthy & get physically active. Calories burned > calories consumed. To tighten ab's: crunches, reverse crunches, exercise ball crunches, pelvic thrusts, lying leg raises, side bridge & “bicycling” exercise on back. Engage in regular aerobic exercise (i.e. running, swimming, Nordic track, bicycling, kickboxing, walking, cross country skiing, hiking, etc.)