When I train abs, I love to focus on the Obliques when I can. Favorite look of the abs for me. These moves are great to target those sides/obliques plus some of these moves also give our mid section some work too.
When I train abs, I always do 3 sets for 15 reps. If it's a move like bicycle crunches or heel touches, that means 30 reps TOTAL since it is a two sided move……15 for EACH side.
Try out this workout it will leave your sides/obliques feeling it!