Winning in volleyball often comes down to the competition between the server and the receiver.
The tougher you can serve, the harder it will be for the opponent to pass and run an effective offensive play.
Serving is the one skill in volleyball each player has complete control of executing correctly. Serving tough can give your team a big advantage, so every server should learn to serve aggressive.
When your players improve at serving, your team will also benefit from this because your players will now have more opportunities to practice passing tougher serves.
So, if you want your team to improve at passing, one thing you can focus on is improving how well the team serves.
The following drill creates a competition between servers and receivers.
For the servers to win, they must serve tough. For the passers to win, they must pass tough serves.