1) Advice about not resting hands or other body parts on winches and traveler (NA for power boat)
2) Instruction on use of the head, and how to conserve fresh water (not leave faucet running etc.)
3) Explanation about use of inflatable PFD's (and I open the Velcro to show and explain the manual inflation valve)
4) Boat rules (e.g. must wear a PFD when leaving cockpit, clipping on at night, when to call me on deck etc.)
5) MOB procedures e.g. 1) throw a float or cushion to mark the position, 2) keep an eye on the MOB etc.
6) How to use the VHF and when

In general I try to explain what we're going to do (and why) before we do it. People are more comfortable when they understand the agenda and can anticipate changes/activities.