LtS is dead right about getting away, not getting even.

1. A choke hold (with both hands) from the front can be broken by bringing your hands and arms up inside those of your assailant and "exploding" your hands and arms outward. This causes surprise and may give you enough time to do something more (e.g., stomp on the instep).

2. A one-handed choke hold can be broken by slamming your arm against that of your assailant and AWAY from your body (i.e., working against his thumb).

3. If you are being choked from the rear, turn your head to the right or left. This puts the muscles of the neck against the hands or, if the person is using his arms, puts your throat into the crook of his elbow. In either case, the point is to make it easier for you to breathe.

4. In breaking a hold or punching someone, punch THROUGH the target area (pretend that the target is on the other side of where it really is). This adds power to your blow or break.

5. Once free, get out of there. And yes, yell LOUDLY all the while your freeing yourself.