This was one of the best drills I ever used to teach kids how to hit a baseball. This drill is also about as easy as it gets. All you need to do is to get a bucket of golf ball sized wiffle balls. Then all you do is to pitch to them from about 20 feet away.
If you are working with smaller kids, get down on one knee so you pitch to them on the correct plane, rather than on a downward plane.
The wiffle ball will travel slower that a regular baseball and it’s smaller too. This helps hand-eye coordination and timing too. Give it a whirl!