Of course every baby is different, so while most newborn sessions take around two hours, I allow for up to three or four hours as some babies require a lot more settling than others. I leave plenty of time for feeding if necessary. If your baby is formula fed, plan for a long session and bring plenty of extra formula and snacks for yourselves. If your baby is breastfed, I have a very comfy rocking chair in my studio and can give you some privacy if you would like. That is entirely up to you, as I am comfortable with what ever makes you comfortable.
I would also suggest bringing plenty of nappies, wraps, wipes and spare clothes in case of accidents. It may help to bring a pram to take your baby for a quick walk around the block if settling in the studio is proving difficult.
When your baby is nicely settled and sleepy, I will try to get photos with different combinations of poses, blankets and props. The variety that is achieved in the photos will depend on how easy it is to resettle your little one during the session.