You got some great advice on equipment etc in the preceding posts. Without trying to sound repetitive, argumentative or stating the obvious, my two cents:
1) Carry at least 5 liters of water per day per person, plus 25%. Carry enough food for 2 full days, freeze dried or otherwise, and all equipment needed to prepare/eat.
2) Calculate your fuel range
in offroad conditions, always know beforehand where your fuel stops are, and have at least a 50 mile reserve.
3) Always know your location and have the ability to communicate that to SAR. Get an Inreach Explorer. It is THE most cost effective emergency communication device out there, anything else is either too expensive without added useful functionality (satphone), too basic (spot/EPIRB), or too unreliable/relies on others (HAM radio).
5) Drive defensively - Just as onroad, this phrase has its own definition in a solo remote expedition context. In desert driving, from my own experience, it means a few things:
- Never drive off into sand without first airing down, preferably to the lowest pressure prudent for the conditions/your vehicle. As you may be aware, the consistency of sand can change very, very quickly. Also, AT tires actually are less good on soft sand than normal HT tires, but may be more durable on harder ground.
- Never stop on soft sand unless you are pointing downhill.
- If you're unsure about what's on the other side of a dune, circle back to the nearest downhill spot, stop and recce on foot.
- In general, going around is better than going over.
- Turn off all electronic nannies (traction control etc.) the second you leave pavement. If you're stuck, the better strategy is to always stop gassing it, and using the sand ladders BEFORE you get stuck deeper.
- A pair of sand ladders (maxtrax/TRED or similar), an air compressor w/gauge, jack support board, bottle jack, tow rope with shackles, and a good shovel are MINIMUM recovery equipment. Gloves and safety glasses are also a minimum.