Hi Mike,
6 pack abbs workout includes weight training exercises like crunches, reverse crunches, heel to ankle touch, konasana, 90* abb crunches, abbs on bench, Leg pushs etc. These exercises are more effective if we combine these exercises with cardiovascular exercises in form of interval training. Cardiovascular exercises are like brisk walking, jogging, running, skipping, swimming, etc. we need to do these exercises in 15-15 min in break along with abbs weight training exercises alternately. Try this type of workout and it may help your abbs building.