Water. Everyone is telling you to take a lot of water. DO IT!
Never, ever sleep or camp in dry riverbeds. Yes, they are soft and sandy and it's much more comfortable to sleep there, but the reason they're wiped clean is because fast-moving water is what does it. It doesn't have to be raining or even cloudy where you are. Water travels downhill. If it's raining upcountry, the water flows DOWN the those formerly dry riverbeds. In a tent or a sleeping bag, you won't have a prayer.
When you get there, pour a little water on the dry sand anywhere. See what I mean? It just rolled over the top of the sand, didn't it? That's what happens to the rain. A light rain, building up gradually, is absorbed slowly. But the desert is famous for cloudbursts like firehoses. It rolls right over the surface of the sand and flows into the lowest areas, which are.... right.... dry riverbeds.
Fast water crossing the road? Park it, Bud. Fools trying to cross them is probably the leading cause of death in many places, desert or not. The power of moving water is hard to imagine until you've felt it.
Wear sturdy footwear. Idiots wear sandals.
Water. Boots. Water. Tarp. Water. Sunglasses. Water. Hat. Water.
Sue, who has been there in August, very carefully