1) Passport Holder for ID - These are nifty plastic ID holders attached to a lanyard that go around your neck. Advice - keep your head on your neck - you won't lose your ID. Lose your head - u won't give a fuck either way. This is good for when you leave camp.
2) Backpack, Ashtray, Rear View Mirror - The point is - make one spot your ID spot and put your ID there every time u take it off your neck. When I was there, I kept my passport holder around my rear view mirror.
The synergy of 1 and 2 is that if you are too drunk or "altered" to a)get back to your camp or b)to remember to put it in its "special place" - guess what!?! YESS campers that's right!! It is around your neck!
3) Keys - why the fuck are you carrying your keys around the playa? Seriously - put them in your glove box or a pouch in your pack and forget about them. If you absolutely HAVE to carry your car key with you because u HAVE to lock your doors - either put them on your ID holder or get a snaplink for them and attatch them to you. Personally, I left them in my ashtray for a week.
4) Camera, trail mix, water, assorted crap - I had a map case I put everything into and just kept it there and replaced or refilled as needed.
Honestly, about a month before I started going out to the playa I started using the neck holder and the key snap so it kind of became a habit.
i might be totally full of shit, bit these worked for me.