What to include in safety brief

[FNG]

You might add in a reference to and demonstration of the bracing position.

After the pre-takeoff checks, and before lining up, I usually say something like:-

"In the event of an engine failure or other emergency during or after the take off, I will land the aircraft. Your actions should be to brace, brace [demonstrating the position as I say this]. After the aircraft has come to a complete stop, evacuate to the rear of the aircraft, keeping well clear of the propeller".

Another thing which you might sort out, perhaps before climbing on board or starting up is the "I have, you have" routine if the passenger is likely to want a go at the controls.

Of course the safety briefing isn't just relevant for the test, and I think that it's a pity that the original poster's instructor didn't instil the briefing into him/her from an early stage. Even the stuff about pedal position and right-seat brake efficacy may be important if you have another pilot sitting next to you (instructor or not), or even an intelligent passenger. When I fly a nosewheel aircraft I usually ask the right seater to test their brake controls. I tend not to in a tailwheel aircraft where the brakes are more for directional control than for stopping.