Bring ALOT of sunscreen, sunglasses, an umbrella in the car or in a backpack(remember 2014's race?). I usually carry a backpack full of stuff the whole time. Bring a camera if you have one. That's the essentials, but feel free to bring anything else you think you will need. Enjoy a long, fun day of racing. My advice would be to walk around especially during the WEC race. Experience all the available spots to watch the race. I recommend going to the front straight do there are seats open for the start and for the end though. By the way, you can still get car corral tickets to do the parade lap, just get the ones not associated with a manufacture. You'll be grouped with a bunch of different types of cars. They let anything do the parade lap.