The trick when teaching a group is to teach a couple and then get them to teach the other children.
The biggest problem I had was teaching the left-handed children correctly.
Lots of my class have taught themselves new techniques using youtube as well. They have made some lovely things - phone socks, bracelets, little soft toys, flowers, placemats etc.
One of my boys has the most perfect technique - his work makes mine look shoddy
The lovely thing has been seeing the huge improvements - the first few weeks they were struggling and they were abslutely amazed that I could crochet and chat simultaneously - now they all sit and chat while we crochet.