Pat, I only started riding this summer so I can't give specific advice for riding but I have taught martial arts before and in order to teach you have to understand EXACTLY what you or others do that makes you/them good. Often before teaching movements I will break them down into parts, execute the moves slowly and think about what I'm doing and how do I relay this information to the student. Sometimes I watch someone do something and know that it's wrong but i'm not sure why. So i'll perform it myself, ahh now I know what's wrong and I can explain it.
You may want to have him ride a few laps and just watch him closely. make mental notes of mistakes or things that you think will make him a faster/better rider. (ie. Use a different line, get on the throttle sooner, lean back more, forward more, bend your knees...) Individualize the training find what works for him. As someone else mentioned video tape is a great training aid, that way you can point out specific things that his is doing wrong or right.
Thanks guys. we have a track right near us ( Tim Farrs practice track) so we go there every day and brake the track up into parts each day. I try to show hom how to do it first and also i tell him what he is doing wrong but i think that video taping is the best thing so he can see for himself. Thanks for the tips.