1) Cut down on sugar: sugar contain glucose and fructose, if you consume large amount of sugary things, your liver converts the sugar to fat and it get deposited in many places, one of these is your abdomen.
2) Cut carbohydrate from your diet: drop the amount of carbs you consume per day.
3) Eat more of proteins: people that eat more protein than carbs are less likely to have abdominal fat. Increase your protein intake. Eat legumes, seafoods, fish and so on.
4) Eat food rich in fiber: if you eat more fiber, you get filled easily. Fibers also slow down digestion process which results in prolong feeling of fullness. Best source of fiber is fruits and vegetables.
5) Exercise: exercise regularly, do more of aerobic exercise like swimming, walking and run.