I find that it depends on what level you are going to be teaching. For me it was always harder to teach a Basic class, especially from day one. I constantly had to remind myself that I had to slow down and simplify things sometimes.
Now if I had an EMT-I or Paramedic class, especially if I knew most of the students, I could cruise along and possibly get into some of what I called "extra stuff". It would be more or less Q & A, but anyone could answer any question. Spread the wealth of knowledge.
A few things to remember for any class, encourage questions. There are no stupid questions. If someone challenges you and says you're wrong, give them the chance to prove it. Most of the time they just hang themselves in the end. If you are proved wrong, chalk it up to a good student (even if they are obnoxious), and that it's something you learned, then move on.
I know these points are pretty basic, but my coffee hasn't got to my brain yet.