The sun can be your worst enemy if you're trying to survive in the desert heat, but it can also be a great way to get the attention of rescuers wherever you are. If you're lucky enough to have an emergency kit at your disposal, then you may have a signal mirror. If not, scour the surrounding area for anything shiny that will reflect the sun's rays, like a canteen or belt buckle. A signal mirror comes with a tiny hole you look through to aim the reflected rays. If you're improvising, you'll have to wing it. The idea is to tilt the signaling device back and forth toward whatever your target is -- a passing plane or helicopter, for instance. Overcast weather and haze and fog will hurt your chances, so get to high ground if possible to improve them.