Staying well hydrated is essential to maintaining physical and mental function, so drink at least a gallon of water per day, and even more in hot environs. Carry iodine to purify water, but if you're in a survival mode and can't treat the water, drink it anyway. Better to chance getting sick than risk not living to worry about it. If your supply runs out, climb to a hilltop and look for signs of water, especially in the early morning when the water table is at its highest, reflections of pools are easier to spot, and birds and insects often swarm wet areas. Don't overlook dew; early morning moisture on leaves can be soaked up with a bandanna and wrung into a container. Vegetation that indicates water includes cottonwood trees (roots can go 40 to 60 feet down, so you might not be able to dig far enough), willows, cattails, velvet ash, sycamore, mesquite, and bermudagrass.
A solar tree still is easy to make. Tie a plastic bag around a group of heavily vegetated tree or bush branches that are exposed to direct sunlight. Rig the bag so that all moisture from the leaves will run down into a weighted lower corner. This yields about 2 to 3 tablespoons in average desert conditions. If you're lucky, you may fare better with an Indian well dug in a sandy wash that drains the area during rain. The hole should be 1 to 2 feet deep and preferably on the outer bend of the wash. It could take up to an hour for water to seep into the hole if it's down there. This method also can be used in coastal regions where no fresh water is in the vicinity. Dig the hole on the inland side of sand dunes. Several wells will improve your odds, and if all you get is mud, wring it out in a bandanna to extract the moisture. When in cold environs, be sure to melt snow before consuming it, because ingesting too much cold stuff can lead to hypothermia.