8 players per court, 4 players as feeders and 4 players as returnees. Change roles after a set time (i.e. 3 minutes).
Feeders: Throw the ball with lots of height over the net in the direction of the player. The receiving player has to be in the middle of the court.
Receiving players: Catch the ball and roll it back under the net to the player that did not have the ball before the practice started. Player should go to the back of the queue after each time.
New hitters rarely miss because of their arm. They miss because of their feet. Build a reliable approach, then time it with your setter.
When your hitter gets stuffed, five teammates standing and watching is how you lose the point. Good attack coverage turns a blocked ball into a second swing.
Coaches spend hours correcting arms in serve receive when the real fault is almost always the feet. Fix the movement and the platform fixes itself.