The first step is the most important. If you start that one off slowly, the rest will "follow suit," as Mainzer said.
Take two BIG steps closer to the foul line. You'll find out that if you're closer, you can't throw as hard because you don't have enough kinetic energy. Eventually, you may move back, but it will feel weird. You will actually "instinctually" move up because you will have practiced it so much.
Relax. Get a high backswing, and once the ball is at the top, let gravity take over, your arm go dead, and the ball do the work. The ball will roll, and not be thrown by you.
If you can keep the Fred Flintstone feet slow, and your arm "following suit," you will make your shots slower. Bowling requires very little muscle.
