Drills to perfect mechanics?

i was wondering if any ine had any drills which would help to perfect my mechanics?
what drills do college, pro players use?

If you want to perfect YOUR style of mechanics i suggets just pitching more.or the towel drill.

The towel drill will help because you can go through your mechanics alot but put less stress on the arm. As far as drills go im not too sure on certain drills that can perfect your mechanics, but there are drills for certain things you want to fix or work on.