One point: at most places I've flown it's understood that if something happens to your plane while an instrutor is flying it or instructing you, it's your loss. This is intuitive when the instructor isn't being paid; why would he accept the risk when he could just fly his own plane? But if you accept money, the student wouldn't be unreasonable in expecting you to take the risk.

If it's just an RTF trainer that you can replace with a couple hundred bucks, you might be willing to do that, but replacing somebody's kit-built baby could be a lot thornier.

Other than that, I'm sure you'll be fine. Make sure you know your lefts and rights; your students generally won't