Start with a 25' Roll Cast, then move to a simple pickup and laydown. Focus on accuracy - give them targets. hula hoops or something similar. (Velcro "hooks" and cloth fish work great on the lawn.) Obviously, roll casts are easier and targets are harder to set up on water. If you're working on lawns keep that in mind and adjust as needed to make it fun and interesting.

Avoid false casts.

Have as many instructors as possible.

Keep the lessons short - 15-20 minutes should be good. Longer than that and kids can get adventurous........

Stop and move on to something else any time is stops being fun!

Cliff