Coaching to Student Class Sizes

The way I have done in the past is: I take 1 or 2 students on a separate table for about 15-20 min and gave multi-ball training to develop their forehand and backhand. Meanwhile, I had a 1300-1500 lvl player overseeing the remaining 20-25 students on the other tables and making sure they were practicing/rallying what I taught them and not throwing balls, etc. At the end, I made sure there was a huge round robin to have fun and just to motivate/stress to them: "See? You lost because you didn't use the swing that I taught you" (hehe). The program included students ranging from elementary to high school.

Keep in mind, the interest levels will be different for everyone so don't expect everyone to be cooperative at first (although just the fact that they voluntarily showed up indicates some level of interest).