drive down for 6 hours from Nairobi or catch a small charter from the Airport. There are many landing strips in the Grasslands and one should land close to the camp they are staying in.
carry warm clothing for the evenings and early mornings. Have your yellow fever shot. I would also carry insect repellents. As far as camera gear is concerned carry your wide as well as long lenses. They all come in use during the course of the day.
As the sunsets the grass lands of the Mara come to life with a different prospective. There is no resting on the land if you are a photographer. Every waking moment is a light with which you paint your image.