Ontrack do a good line of overheads for the briefing of the exercises.
A couple of bits of flip paper across them and you start from the top and work your way down. Or use them as a reference as you do the board work.
It does get easier to the point that you almost slot a tape into your head while you instruct a exercise. So much so when you take your mate up on a trial flight they say that they didn't reconise you.