If you think you have enough material, you do not. Once you've picked a concept to teach, have plenty of options and alternative routes to get there.
If you think you've practiced enough, you have not. Drill, drill, drill... and then do not neglect exploring options after that, so you can better anticipate what questions and concerns will arise.
They will not absorb the lesson the way you'd have absorbed the lesson. In fact, you will need to explain details you'd taken for granted, and they will notice new details you've never noticed, partly because they're seeing it with fresher eyes, and partly because they're different from you.
When you learn... ALWAYS. ASK. WHY. Drill it first, and then explore.
Similarly, sparring is playing, and playing is not drilling. There's a time to explore, and there's a time to drill, and you need to distinguish this clearly.
"When you're in command, command. You're in charge now, so take charge." – Paul Slush