Contour drawing of hands are one of my favourite lessons to teach and I teach a variety of them. Students start off thinking there's no way they'll be able to do a realistic drawing of their hands, and then, with time and careful observation and practice, they are able to draw some pretty impressive hands. I usually start hand drawings in Grade 9 when I feel ALL of them have the patience and skills to be sucessful at it.
The Incredible Art Department website has loads of different hand-related lessons for mid-high:
For this lesson, kids started out doing blind contour drawings of their hands. Then moved onto continuous contour drawings of their hands. I gave them a brief intro into American Sign Language (ASL) and gave them a handout showing all the hand poses. Then they choose a word (their name, etc.) and draw their own hand in the appropriate pose. They do these on individual sheets of regular printer paper.
When they have their hands finished, we graphite transfer them onto heavy white paper. Then pass over the lines again with pencil, then they do abstract shapes of really transparent watercolour over the hands.