Joser -
Definitely adjust the suspension, or you'll be see how light the front is when accelerating, and how much it dives when you stop. I've gotten away with just adjusting the pre-load on the rear for spontaneous rides, but if you have time, do it all.
Like someone already said, make sure the passenger knows to lean with you, and practice a few turns before getting into traffic. My wife got freaked out on one turn and leaned the opposite direction and we barely made the turn. Lucky it was just in out neighborhood! Passengers can get target fixation too!
Passenger can reach around and brace on the air box when stopping to help transfer their weight.
Also, make sure they hold their own weight up or it will be getting transferred straight to your wrists if they are leaning on you.
smooth braking and consistent shift points will help them predict the changes in acceleration.