When intraining for abs firstly realise that you have to have a low fat percentage to be able to see the shap of your abs, a good percentage is 9 to 12% body fat.

I have researched this topic as it is something that comes up time and time again, and from what I've read there does seem to be a pattern, what I found out that you dont do is crunch after crunch after crunch using just your own body weight, you would have to do 200,000 crunches to lose 11 pounds of fat off your stomach so crunches are not designed to lose fat, you have to have a good diet and carido workout for that.

Resistance training for abs is best, doing 10 crunches with a weight is similar to doing 100 crunches without. Try movements with barbells and weight plates, try chin up ab crunches. Using weights and performing slow movements will build up your abs in no time.