Starting on the attack line, the players imitate a dig. Then, they jog forward to perform a spike movement. On landing they then move forward to the net to perform a block movement, land and jog backwards to their starting point on the attack line.
You should ask that all players do this drill at the same time. This will help them to focus not only on themselves but also watch the court to improve attention divisibility as well.
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.