1. Get yourself some Pedialite
The number one rule of filming in the desert? Drink a LOT (and sometimes something other than booze). Every day on our set, most people drank an average 7 bottles of water + 3 bottles of rehydrating drink (coconut water, gatorade, or electrolyte tables in water). And still, in some cases, it wasn't enough. And when it wasn't, Pedialite saved our movie. Maybe it will save yours. Either way, don't throw caution to the wind, have some Pedialite and use it at first signs of heat exhaustion! (I do not, nor have I ever, worked for Pedialite. But hey Pedialite, you hiring?)
2. Wear shoes
Snakes, spiders, gear, goes without saying. Then why am I saying? Because when it's 115 degrees out, it gets tempting to throw on the old Reefs. But if the wildlife and gear isn't enough to persuade you, keep this in mind. Some days it was so hot on set that the ground started burning me right through the soles of my Tom's.
3. Even if you're John Boehner, invest in sun tan lotion
You will need it. And so will your poor PA friends. Someone will get burned almost every day. Oh, and when they do, Vitamin E liquid, goopy, sticky, right on the skin. It will help a lot.
4. Make like a bankrobber...
...and get a face mask. Okay, so no, it doesn't have to be one of those lunatic ones with eye holes, but get something to cover your face. Because when the wind picks up (as it will) and the sand starts flying (as it definitely will) you'll be glad you have something with which to cover...every part of your face, and all the openings on it.
5. Find the closest free pool. Then invest in some gifts for the guard of that pool. You will be glad you did.
6. ENJOY! Remember, somewhere in the world, it's snowing.