The answer:  There is no secret!  The reality is you can train your abs every single day for up to 150 reps per set for three sets or more and take as many thermogenic supplements in existence along with some fad diet and still not acquire the elusive "six-pack" abs.  Why is this the case?  As long as your bodyfat level stays above 10% you will not be able to see abdominal definition.     
    Yes folks, the solution is simply dependent on your body composition--namely how much bodyfat you have.  Spot reduction is a myth and performing seemingly endless ab exercises in the pitiful hope of reducing the size of your belly will ultimately end in miserable failure.  You cannot target fat loss from specific areas of your body by simply doing any exercise you can imagine.  You cannot control which areas of your body you want to burn fat.  Fat burning is a holistic process meaning that overall bodyfat must decrease in order for defined abs to appear.  You can stimulate abdominal muscle strength but you cannot burn bodyfat.  So at best, you can strengthen your abs by doing crunches but you will not see them.  It is just not possible as your body does not work like that.
     You do have "six-pack" abs but their appearance cannot be seen since there is a layer of fat just underneath your skin called subcutaneous fat that is obscuring your ab definition.  So having said all this, how do you go about getting those "six-pack" abs that you desire?   The answer is simple but apparently not easy to do for most people:  eat a healthy low-fat diet and perform regular weight-resistant and cardiovascular exercise.  Your focus should be on eating six to eight small meals per day (e.g., eat every two to three hours) while gradually decreasing your caloric intake per week.   The foods that you eat should be relatively high in protein and fiber and low in refined carbs and saturated fat. In addition, you should drink plenty of water (e.g., about one-half of your bodyweight in ounces) throughout your day.  Read my blog on tips on how to lose bodyfat for additional things you can do to facilitate the appearance of those almighty "six-pack" abs.