One thing I've found helpful to control "snaking" is to make sure my feet stay close to each other while kicking (big toes tap each other). Make sure your head isn't too far out of the water or your legs will sink, and you will instinctively kick more to keep your lower body up. Using those TYR EBP fins have done wonders w/correcting my body position in the water.

Agree w/HillSlugger---focus on one thing at a time.