Having a 6 pack abs, is very easy to imagine, but very hard to do. You always need to do crunching, sit ups, more pain inyour gut, without seeing any effect of those hard exercise, what you don't realize is to build a 6 pack abs not just need to concentrate on the rectus abdominis, but you also need to work other group of your muscle. Including the quads, the obliques and the back muscle, if you maximize those muscle groups plus the abdomen you will see results in no time. You also need a very good diet to see the underneath muscles of the abdomen, 6 pack will not show up even if it is big if there are fats covering them. What I do to get rid of those fats in the abdomen, is the diet that I called "supermeal" I eat carbs in the morning as well as meat and vegetables, I also eat the same type of food in lunch, but during night I only eat pineapple. I get rid of 2inches of my belly fats in 2days no kidding, try it to see it for yourself.
Watch some video for the abs exercise