Well step one is to ignore the idea that doing countless crunches is going to give you abs, and start listening to a professional. This is what my degree is in, and I've personally done it all my self so I know it works.
Step two is to train your ab muscles based off the functions that your abdominal muscles are suppose to handle. AKA: Supporting your spine.
Squat with heavy weight, and go below parallel. Don't use a belt until your latter working sets.
Deadlift a lot of weight. Again, don't use a belt unless you absolutely need to. Use chalk instead of lifting straps so you can still work your forearms.
Any other heavy compound movements will also help your abs. EG: Strict Military Press.
In terms of isolation movements. Pretty simple:
3x20 on either a weighted ab movement (Like Cable Crunches. Not dumbass Nautilus machines where you're using your biceps not your abs). Add more weight each time you come back to the gym. If you don't have access to that equipment, do decline crunches with a dumbbell weight.
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Hanging Leg Raises for the lower abs.
Your abs are a muscle group just like every other. The only difference is they actually are being worked with most compound physical activities. Don't do them 7 days a week or you won't be recovering from you workouts and thus make 0 progress. Your ab genetics are 100% unique. What bodyfat it'll require to show them, let alone of them ripped is based off how your body stores fat. Hell, whether or not you can have a 4 pack, 6 pack, or 8 pack was decided at birth. Additionally: your diet will be a lot more critical than your exercise routine. Finally: make sure your progressively overloading.
Closing Point:
It's a lot harder to sculpt a pebble than it is to sculpt a slab of granite. Meaning: if you don't have a lot of mass on your body to begin with (like benching 200+, squatting 300+, deadlifting 400+) you probably don't have any business trying to get abs. You'll be "skinny fat" even at ridiculously low body weight. This is why skinny little punk kids in high school have rib cages, not amazing abs.