If you're going to do it, do it right. Exercising with poor form at the least gives you poorer results, and at worst you can injure yourself.

On the days when you don't work out with a trainer, you can use these clips to learn the correct form.

Barbell Biceps
Cable Biceps
Cable Rows
Calf Raises
Lat Pulldowns
Leg Curls
Leg Extensions
Leg Press
Pec Deck
Smith Machine Bench Press
Triceps