Here's how to get them. Start out simply standing on the ground flatfooted, toes pointing straight ahead. Hold on to something to balance yourself, and begin raising up as high as you can on your toes. As with most exercises here, you will do them slowly. Lower yourself to the starting position, then repeat.
High reps are best here.
Try to work up to at least 25 reps. To make this a little tougher as you progress, do them one leg at a time. You can also turn your feet in and out in order to work different parts of your calves. A set of 25 reps with feet pointing forward, then out, then in, would give you a nice workout. For an even tougher workout, and to really make those calves grow, place your toes on the edge of a 2x4, or on the stairs, and lower the heels as far as possible.