And I agree with Mac .... take samples for show and tell!
Take lots of samples!! The good, the bad and the ugly, too.
All that practice work will not be in vain,
and can show them a lot more than you can ever tell/demonstrate/instruct.
I know it has helped me at classes, when an instructor can say, do it this way, because if you do it this other way, it will look like this. Seeing the two differences often means a lot more to me (and I am sure others) than to just be "told" and perhaps not quite understand the meanings behind what is being said.