Practice throwing in movement.

8 or more players, 2 balls

Players 3 and 7 move to the middle and get the ball from the right off players 1 and 5.

Players 4 and 8 throw the ball to players 5 and 1 who get the ball from the right.

After receiving the ball players 1 and 5 throw to 6 and 2.

After the passing the players follow the throw to their new position.

Players 2 and 6 throw the ball to 4 and 8 who get the ball from the right.

After receiving the ball players 4 and 8 pass to 3 and 7

After the passing the players follow the throw to there new position.

Variations:
You can let the ball come form the left instead of the right.
Throw the ball low instead of chest height.