Stand facing a partner on the other side of the net and about 1 metre behind the 3 metre line; throw the ball using two hands underarm over the net to land on the 3 metre line.
The partner touches the floor with both hands as the ball is travelling towards the net then moves forwards, turns to go backwards with feet apart over the top of the ball. Player must be moving towards the net and not jump over it.
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.