If I'm in the wilderness in a dry, hot climate without much vegetation and I'm running low on water, what land features and other potential signs can I look for to guide me to a drinkable water source?
I never tried, but one option I read about is to tie a transparent plastic bag around a branch of a large leaf tree, and let water condensation from the plant to stick to the inner wall of the bag. Cut a small hole in the bag and let the liquid drip out.
An alternative is to dig a hole, put anything having a water content in it, add a cup at the bottom of the hole, cover the hole with a transparent plastic sheet, put a rock in the middle, and let the sun evaporate the water. This technique is called a "solar still". One note of warning with the solar still: digging a hole requires sweat, and the amount of water a single solar still provides is small. A solar still in a very hot climate may be a net loss of water, but I speak from gathered info, not experience.
When it comes to territory, clearly you will likely find liquid water below the timberline. Water follows the gradient, so keep into account the watershed and look for features that form confluences, such as V-shaped bends.