A few things I recommend bringing with you to Elephanta:
1- A good book to read on the hour-long ferry ride.
2- A hat if you're sensitive to the sun.
3- A bottle of water (although drink-sellers are abundant on the island).
4- A snack or a packed lunch (again, a few restaurants are available on the island).
5- A torch (flashlight) for a brighter look at some of the sculptures.
6- A camera stand if you would like to take sharp pictures of the sculptures within the dark caves.
Wear light cottons if in summer or slightly warm clothes in winter. Always wear closed shoes without high heels as there are a lot of uneven stone steps you have to climb to get to the top of the caves complex as well as get in and out of the boats at the jetty.
Photo Equipment: Get all your photographic supplies because if you run out of anything usually it will all be available but for a very high price!!!
Miscellaneous: Everything is highly overpriced over here so get whatever supplies you want for your camera. Even drinking water is more expensive to buy here.