Most [tag]baseball[/tag] coaches will teach their hitters to swing down on the ball. When you watch professionals in the batting circle, they are swinging down towards the ground. This helps prevent swinging upwards and creating fly balls.
What you need (set up): Tee (or pitchers) and a [tag]batter[/tag] with an infield. 
How this drill works: Either with a tee, or with a pitcher, in this [tag]coach pitch baseball drill[/tag] balls are hit downward into the infield. Each time a batter hits a grounder they get a point – up to 10 points. If they hit a line driver they get zero points, if they hit a pop up, they lose all of their points and must start again.
Results: This drill will help people to swing down at the ball, to reduce the number of times the ball pops up in the air. Pops up are easier to defend and play for the defense, and ground balls are going to be hit with regularity by players who utilize this drill.