If you find yourself leaning on the tails of your skis, or "in the back seat" while skiing, most likely you're not making a clean, precise turn.
Here's a tip to help you "drive" your skis from the front. As you ski, slightly lift your toes up inside your boots. Also, think about feeling your shins against the tongues of your boots. By lifting your toes and pressing your shins forward, your ankles will flex, automatically putting you forward on your skis. With toes lifted and ankles flexed, you'll be able to control your turns much more effectively than if you're back-seat driving.
-Elianne Lippetz, Squaw Valley, Calif.