1) for ab thickness i really like that cable rope crunches and weighted decline sit-ups
2) one of my favorite workouts is to alt. between weighted exercises and bodyweight:
Cable Crunches: 3-4 sets of 8-12
Roman Chair Leg Raises: 3-4 sets to failure making sure its controlled motion
Decline Weighted Crunches: 3-4 sets of 8-12
Briefcase crunches: 3-4 sets to failure making sure its controlled motion
3) one of the main myths i believe is people thinking that doing crunches and abs everyday is going to give you a six pack. It really all comes down to diet and lowering your bf% in order to have your abs show. There are also many sides to how to train abs. Some don't train abs directly because they believe doing the compound lifts and keeping your core tight will train your abs enough and the other side thinks different. I feel you have to see what works for you.
4) sorry btb, i have no tricks