Getting started: Get your shoulders situated under the pads of the calf machine or under the bar if you are doing these on a Smith machine. Then, situate your feet on the platform or block. The platform you use should be high enough to get a really deep stretch on the calves at the bottom of the motion. Make sure your feet are pulled all the way back off the edge with the balls of your feet still securely on the platform. You can do these in a variety of foot position angles to target different parts of the calves. If you do not already have some significant calf development, don't do these different foot positions immediately. Stick with the basics for awhile.
For the first toe position, put your feet about six to eight inches apart with your toes pointing straight ahead. That is the basic form for most calf exercises. If you are trying to target the inner calf, put your heels together and point your toes out. If you are trying to target your outer calf the put your toes together with your heels pointing out.
Start at the top by standing up on your tip toes as high as you can, flexing the calves and holding the contraction for a second, then releasing slowly (inhale here) into a deep stretch. Pause at the bottom for a second, absorbing the stretch into the calf, then flex it back up to the starting position (exhale here). The key to great form is getting the full range of motion and flexing at the top.