As strange as it sounds, have them practice body isolations, like from dance. You teach them to hit four corners with their ribs, their hips, their shoulders, then have them do it in sequence (front back side side, etc). Once they can isolate specific muscle groups, the ability to control and strengthen those specific areas becomes easier and better understood. They begin to get the feel for the areas they need to tighten and the areas they need to stretch and strengthen. I was a dancer all my life and found that once I could do this, everything was tighter, more precise, and actually came more easily to me, and being on pointe is similar to being up in someone's hands (not the exact same, but similar-you need alot of the same core control).
