For youngsters start with a non partner dance. Try to make the dances as non sexist as possible in any talk through. eg tallest person on the left. Boys dance with boys in clubs these days - show no surprise if 2 boys dance with each other. It takes a bit of doing to rethink what language you would usually use - avoid ' man and lady'.
Demonstrate rather than try to explain if possible.
Try to make the dances progressive in that each dance has only one new bit. eg bridge of Athlone has a cast. The next dance could have a dip and dive and a cast.
Do dances at 2 speeds or gradually speed up- the second speed as fast as you think the dances can be sensibly danced. Youngsters can dance for longer than we oldies.
During the break give them enough time to put the date of the next dance in their phone
Finish with something like a 2 person down strip the willow ( no other moves ). One long set - with several couples going down at the same time. Expect laughter and mayhem.
Have fun.