Full Tutorial: http://www.musclehack.com/build-muscular-calves-with-calf-raises
This is how I perform the seated calf raise with my Smith Machine.
The balls of your feet should be just on the edge of the foot rest. This will allow you to achieve a full contraction.
TIP! When you think youre at the top of the rep, try to push up an inch higher!
Please read the full tutorial here:
Full Tutorial: http://www.musclehack.com/build-muscular-calves-with-calf-raises