One way to do it, and this will sound strange, is with a popsicle stick. When I was young, I had my teeth grow behind my baby teeth, and we moved them into place using a popsicle stick.
The orthodontist actually was the one who showed us how to do this. Here's how to do it:
1. Get a popsicle stick.
2. Push the popsicle stick against your tooth in the direction you want to move it for about 90 seconds.
3. Do this each day.
The time it takes for this to finish depends on how much you want to move it, but it's the best method I've found for moving teeth, and I'm actually doing it right now to move my top canines out a little bit since they're too long and come down on my teeth. You'll start noticing change within the first couple weeks.