Mark Rosen of the University of Michigan talks tough serving. His team's goal? Score serving streaks by serving hard, consistent balls. Every time one of his players serves, he expects them to earn two points in a row.

The first goal: Get the first ball over the net, and make it tough. This can mean several different things: a speedy serve, a serve to a certain location, a serve that targets the weakest passer, or a serve that lands between two players.

The second goal: Make the second serve a little tougher, so ramp up the speed, accuracy of location, or trajectory.

Once you've scored two points in a row, that constitutes a run. A run can make the other team feel defeated or panicked, so a serving streak can be a powerful tool to shift the course of the game in your team's favor.