Bring as little food as possible that needs to be cold at all times. Sure, some is good, but when it gets melty and packaging begins to leak, you're headed for a food disaster of epic disgusting proportions. Think beef jerky, canned tuna and beans, granola bars and top ramen.
(on this note, a good tip I learned last year - bring some ziploc bags to put the cubed ice in. This way, when it does melt, you at least have cold DRINKABLE water and less cooler soup to avoid.)
Bring grocery bags to carry in your backback when you head out onto the playa for MOOP pickup. This way, that dusty can won't get stale beer all over your backpack necessities and you can always find that feather that you were sure you picked up earlier.
Buy some mini-flashlights. I like to attach mine to a string for nighttime easy access when you need to check the gross factor of a porto-potty at 4am on the playa. (I'm buying lots of extras, string attached, to give as gifts to some people in need of nighttime potty lighting - so helpful!)
Bring some multi-vitamins. You are never getting the nutrients you need and multi-vitamins are great to keep you healthy and energized with plenty and vitamin-C. It has all the good-for-you help you'll need to get over that tequila hangover in the morning so you can keep exploring! (Plus, it's good to be able to give to your neighbor that looks destroyed at sunrise. It might just save their day).
BRING WAY MORE WATER THAN YOU EVER THINK YOU COULD CONSUME!! YOU WILL DRINK IT!!! (it's good to bring something to mix with a jug for a tasty refreshment. I like Emergen-C as you get an extra boost of the vitamins you need out there. Or powdered lemonade - it's good to mix with vodka. yum.)
I like bringing a carton of cuties (of clemintines, whatever you call them). They're small and easy to bring with you out on the playa for a mid-day snack. Plus, you can bring a few to give to a new friend who maybe hasn't eaten much in 2 days. Just make sure you have somewhere to put the peels so you can lug them away at the end of the week! MOOP=bad karma
i'm on the playa, bitch!
bigger and better next year, every year...