I'm lucky enought to have a body that's a fat burning machine, so I can't comment as to diet. Once you have your diet under control and you can see your abs you'll know better where you stand.

If you want your abs to be more apparent; if you want them to grow then consider a better way to work them. If you keep just adding reps to situps or crunches your abs will stop responding eventually. Your body will adapt and your progress will stop.

Consider adding other ab exercises like jack-s or hanging leg raises. I just do weighted crunches and do some other things here and there.

I've never really understood the rationale behind doing hundreds and hundreds of ab reps. Even if your abs are just where you want them then you can still just add a little weight to maintain. It's much more efficient.

But there is a miuch better reason to work you abs than a six-pack. Along with your lower back they are what stabilize your torso; keep you upright.

Failure to maintain a strong midsection is one of the things that lead to back injury. I've known people who use heavy weights doing deadlifts, SL deadlifts, rows, whatever, and then just do some crunches now and then for abs.

This is a bad idea. You do not want a strength imbalance between your back and abs. They work in concert almost all the time, whether you're aware of it or not.