1. Before throwing, be sure to check the "tune" of the boomerang. Lay it on a flat surface and press down at the elbow. There should be a slight upward bend at the wingtips. If not, gently bend the wings and hold for a few seconds, then check the tune again.
2. Check the wind direction (if any), and throw with your left shoulder (assuming you're right handed) into the wind.
3. Hold the boomerang with the flat side away from you. Hold firmly but not too tight. I use any of the three grips illustrated. Use either wing. Try both to see which works best.
4. Tilt the boomerang over to one or two o'clock. Never throw it flat like a frisbee.
5. Throw the boomerang overhand. Raise it over your shoulder, then release it with a good snap of the wrist. Release should be about shoulder height.
6. Catch the 'rang by sandwiching it between your palms. Keep the fingers out of the way. Keep in mind that there is a difference between a boomerang coming back to you and one that's coming at you.
Imparting enough spin on the boomerang is what it needs to return. Often good spin is more important that the power of the throw. A proper balance between the two will be reached with practice.