Okay, here is the real way to do it:
Don't clamp!!! Almost all people in high school/middle school only know of faceoff moves that start with the clamp. Let me teach you a different one that was designed to beat the clamp. It is called the jam.
Okay, lets start with hand position. You should alway use the motorcycle grip, it gives you more control, and a better response. It may take more time to get use to, but it is totally worth it. Okay, now, on to the move.
Instead of clamping on the ball, you want to lift your stick off of the ground, and put the bottom sidewall over the ball. Then put the bottom sidewall on the ground on the other side of the ball. Next, you are basically clamping with the face of the head, instead of the back. Just rake it out, and you win!
The idea is that when you bring your stick over the ball, you hit the top sidewall of the opponents stick with yours, thus being called the jam. Then, you can get under their stick, and win the face off. Here, let me take some pictures to help.
Not my greatest photography, it is hard to hold the stick and take pics at the same time. Anyway, here is the starting position, from opponents view:
Step 2: Lifting stick over ball
Step 3: Placing stick on other side
Step 4: Clamping on other side
View from your side
Get it now?
Man, maybe I should make a face off tut...