Make sure you talk them through what to expect when pulling away and stopping (had a few pillions come flying forward when I brake, crushing me against the tank!)

I always tell them to tap me on the leg if they want to stop, and reassure them that they won't come off the back!

Oh and be prepared for newbies to lean the opposite way on corners..it upsets the balance of the bike a lot and is a bit of a fight, but they get used to it soon!