Introduction of basic tactics; throwing the ball into space on the designated court, catch in a volley position in front and above the forehead and throw from a volley position in front and above the forehead. You can't move with the ball and must face the net at all times.
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.