I am a Ranger in the Palm Springs, CA area and many people like to come out to the desert and go for a hike. The desert is one of the most beautiful places in the world and one of the most dangerous. With just a small check list you will be able to hike safely in the desert. Hydration is the first and most important thing when coming into the desert. Just having water is not enough, you must hydrate your body the night before. This ensures the cells of your body will be hydrated in the morning when you go on your hike. The water you drink during your hike will help maintain your hydration for the duration of your hike. I recommend at least 1 quart of water per hour, that means on a 8 hour hike you will have to have 2 gallons of water. Another rule of thumb is once half your water is gone go back so you know you will have enough.
The second most important thing is to hike with either a friend or a group and tell someone where you are hiking and when you should be getting back. The desert looks the same in many places and just getting off the trail for a little bit could mean the difference between exploring some unexplored areas or wondering if whether or not someone will be coming to save me. Most of my rescues have been searching for experienced hikers who decided to hike on thier own. If you do get lost DO NOT move around thinking you can find your way back. Stay in one place and wait for help. I personally have a 95% recovery rate where the person has waited for help and only a 65% recovery rate when the people have decided to move around.
Third, bring some light food stuff. I recommend some trail mix and some fruit. I would stay way from heavy food stuff like can foods and meats. Not only is the trail mix light you will be able to stretch it out longer than a can item or a meat item. If possible, find some electrolyte tablets and use the during the day.
Fourth, either wear layers of clothing or bring some extra clothing, the desert can change in temperture within hours. Always cover you body the best you can while in the desert especially in the summer when the Sun will be cooking your skin if exposed. A good hat that covers your head and neck is the best. I recommend you always carry a bandana, you can wet it to cool you down or use it in first-aid when needed.
Fifth, have a good map or gps and know how to use it.
Sixth, and lastly bring a small camera for those pics you will only get from the desert. I hope this will help a few people on thier hikes in the desert and will be able to enjoy the beauty of the desert. Please remember while you are out there the desert is very fragile. So take only pictures and leave only footprints.