Don't forget to create a teaching plan with an organized progression from beginning to intermediate to advanced techniques/exercises.
Also, prior to each class, write out your plan/goals for that particular class. You don't have to follow the plan necessarily, but if gives you an outline and an organized way to proceed.
When I was teaching, Kung Fu not qi gong, I rarely followed my teaching plan other than to use it as a general guide. I freely changed the class according to my own inclination at the time and/or according to teachable moments created by student questions or what I perceived to be a weakness that required attending too, etc.
FAITH: "Confidence, born of experience"