@Jester39 - Another good thing to teach new boaters is how to tie a bowline knot if you're planning to get their help when you dock.
Sometimes you'll dock more than once if you're stopping for lunch at an island restaurant or dropping anchor at a remote island. Either way, it's always nice to tell your passengers before you get started exactly what you'll need them to do to help you.
I would also teach them the difference between port, starboard, bow and stern before getting out on the open water. And last but not least, show them where the emergency equipment is stowed. That should be a given!