Couple of points.
As JP says, light and experienced is always good. But if either of these are not available to you then first point is to be ready for the weight swing when they get on. A lot of bikes these days have high passenger pegs. so a lot of leverage all of a sudden. especially if your feet are in gravel like in a layby.
the second one is beware of pillys who take it upon themselves to lean round corners independently of the pilot. You will definately know when this happens. the first time they do it to you, you may mess your pants. depending on your entry speed.