Strength train at least 3 days a week. This will help boost your metabolism and help you burn more calories even at rest.
Ditch the "500 crunches" workouts and do more intense core work with exercises like windmills, Turkish sit-ups, hanging leg raises, etc.
Perform 2-3 HIIT or high intensity interval training workouts a week. These need not and should be long in duration, 10-20 minutes is enough if done correctly.
Get more active. Even if you spend 1 hour a day in the gym on all days of the week, it is still just 7 hours of a total of 168 hours in the week. Try to make the best of the remaining hours by getting more active. Plan playtime with friends/kids, and move a lot more during the day.
Get 6-8 hours of sleep each night. Less than that and your hormones will always be in a fat storing state, and you will find your dreams of a flat stomach hard to realize.
Meditate, and use other stress reduction strategies that will keep your cortisol levels under control and keep you from gaining abdominal fat and not make you age faster.
Eat more protein, fiber, and healthy fats. This means more lean meats, veggies, and nuts. Eat less junk, refined and sugary foods. These are the worst enemies of a flat stomach, and they are often the cause of many other chronic diseases like diabetes, hypertension, etc.
Drink more water, at least 2 liters a day is a bare minimum. Less than that and your body will not be able to burn fat most efficiently.
These are some of the best tips you can get to lose abdominal fat and flaunt a flat stomach. Want it? Then lose it and flaunt it!