[Lots of truths in that list no matter what you are teaching. And while I know everyone categorizes certain types of knowledge I believe this applies to everything. You can always teach what you know, regardless of topic, but I do make one request. Only teach what you know by doing. If you can’t practice the thing you’re teaching (lots of topics leap to mind) then maybe it requires some level of certification. If you’re not a surgeon, maybe trying to teach surgery is a, er, um, less good idea.]