Boomerang circles but lands in back of you. Boomerang circles but returns short. Throw harder, or use more spin. Boomerang flies high over your head and past you. Throw easier, or release the boomerang in a more vertical position.
Boomerang climbs straight up and then dives to the ground.
This is THE most common problem. It should be nearly vertical when released. Boomerang dips in flight, and may hit the ground. Boomerang was thrown with too little layover. Throw with a little more layover.