Make sure you have control when she gets on the back. Both feet on the ground, holding handlebars with both hands.
Check she is on and comfortable before setting off.
Advice to me was always to tell the pillion NOT to lean, just move with the bike. I had a friend ride with me last weekend and he was leaning into corners and it was actually very off putting as the weight distribution wasn't where I was used to it.
When you have stopped, you stand with both feet on floor and holding the bars and signal she can get off.
Make sure she holds on tight.
Make sure your gear changes are as smooth as possible and take an easy ride. Pillion riding isn't the best time to thrash the crap out of the bike.
Edit:- Just thought, if you aren't used to it, Pillion affects you a fair bit. As mentioned above in handling but also in acceleration and most importantly braking. You are carrying more weight so more distance to stop. Quite vital bits of info when you are used to bombing about on your own and then have someone on the back to change your usual perceptions.