I was 6th or 5th kyu leading training in the University club on the night of the week that the instructor couldn't make it. I'd just try to repeat what we did in the other session when the instructor was there, but it forced me to pay close attention to what he did.
What you said there triggered off a memory I had forgotten. At first I was teaching very much the same as my teacher, well as much as I could anyway, which led me to a strange place. I found in the end I was more trying to be him than be myself. Another valuable lesson learned.