Hi, Luis!
For well-trained and defined obliques, you want to get in a lot of the following:
Crossover crunches (where you're bringing the shoulder toward the opposite hip) (legs in varying positions, including feet on floor / knees bent, legs flat on floor, feet on an elevation, one leg elevated)
Side-lying crunches with legs elevated
Bicycles
Med ball seated torso twists
Reverse crunches with a twist at the top (check out Core Max routine #1)
Stability ball knee rolldowns with a twist at the bottom (again, check out Core Max routine #? {the one with the stability ball})
Hip dips with or without added weight on the torso
I don't know, from what you've posted, which Cathe ab / core routines you have and are doing regularly. Why don't you post more specifically what you're doing here, and we can offer more suggestions?
A-Jock