Make Water in the Desert

Dig a few curved holes (the more the better) about half a meter deep so that the moist subsoil is clearly visible. If you are in dryer conditions, dig the hole a bit deeper, as it is essential that the moist subsoil is clearly visible. If there are any plants, throw them in the hole as well.

Survey the land for signs of dried out river beds; these are the best places to seek moisture.
Do not dig the hole in the shade. The process needs direct sunlight to work correctly. Look around and make sure that shade won't move over your solar still before evening arrives.
You may lose more water perspiring while digging than the still will generate for you in the end, depending on the moisture in the soil, how hard the soil is to dig, and what you're digging it with.
Urinating in the hole provides extra moisture and is sanitary because only the water evaporates.
This technique can also be used to purify dirty water, including urine[1]--anything but radiator fluid.[2] Instead of digging a hole, replace the hole with a larger container containing the tainted water and do everything else the same. If you don't have a container, pour the tainted water directly in the hole.
Place an open coffee can, mug, cup or canteen in the center of each hole. If you have a length of plastic tubing, you can run it from the bottom of the coffee can out the edge of the hole. You can use the tubing to suck the water from the can without dismantling the still.
Lay a taut piece of clear plastic wrap across the top of the hole. To create a seal, pour sand in a circle around the hole along the outside of the plastic wrap. Pour the sand an inch or two from the edge of the plastic wrap. Ensure that there are no gaps not sealed by the sand. The plastic wrap must seal the hole shut; if it is punctured the water will not condense.
Place a small to medium sized rock in the center of the plastic wrap so that the plastic wrap dips to a point above the can. Keep the plastic wrap from touching the can or else the water will not drip into the can.
Sit back and wait for the sun to evaporate water out of the moist soil and any plants you threw in there. The water will condense on the plastic wrap because it cannot escape the hole and will drip into the can. If you have the plastic tubing, drink from that.
Once the sun dries the subsoil in that hole, start the process all over by digging another hole or just dig deeper.


Plant Condensation
Put a clear plastic bag on the end of a plant or small tree branch.
Make sure the bag is sealed as tightly as possible around the branch. The plant transpires water during the process of transpiration. A clear plastic bag is necessary to maintain photosynthesis.
Water vapor will collect and condense in the bag. Make sure the water collecting in the bag won't drip out.
Wait until evening for maximum condensation before removing bag.
Switch the bag to another branch and repeat.


[edit]Tips
Make sure you leave it long enough for the process to take place. In somewhere like the desert where it is really hot, it should take a couple of hours; in places with less sunlight it can take half a day.


[edit]Warnings
Contrary to what is written in some popular survival books, the solar still will not provide adequate water to keep a person alive, even if it is constructed in moist soil. It is a last resort, so don't wander into the desert without enough water, thinking "Oh, if I run out, I'll just suck water out of the soil!" Those might be your last words.
This survival trick is actually far more useful in purifying water that may be contaminated than it is for obtaining water.