Coach Joe Dinoffer has a neat drill designed for younger players, but it works well with all ages.
Transcript
Although, this next drill is especially designed for younger players, it works well for all ages. The only props required are different color markers. It goes like this, as the youngster prepares to toss the ball; the teacher calls out which target they should try to hit. The teacher should wait until the thrower is in the middle of their motion before calling out which color they should in for. This will force them to develop a specific motor skills found in wrist and hand movement instead of full arm movement to control the specific distance and direction of their throw.