Anyone who spends much time in the outdoors should carry and learn to use a compass, unquestionably an essential survival tool. There are many excellent books on the subject, including Be Expert With Map and Compass: The Orienteering Handbook, by Bjorn Kjellstrom (Scribner's, 1976), which is currently out of print but should be available in libraries, and Staying Found: The Complete Map and Compass Handbook, by June Fleming (Random, 1982), sold in most bookstores for $4.95.
In addition to honing your skills in the use of man-made direction finders, you may well want to know something about sun compasses.
Use a Sun Compass!
As everyone knows, the sun always rises in the east and sets in the west. It follows, then, that shadows invariably move in the opposite direction — a fact that you can use to plot true north any time the sun shines.
Find a stick about a yard long and push it into the center of a fairly level and brush-free spot of ground. The limb doesn't have to be vertical; you can lean it, if necessary, in any direction that gives you the most convenient shadow.
Once the stick is securely positioned, mark the tip of its shadow with a stone or twig. Then wait 15 or 20 minutes (or until the shadow's point has moved a few inches) and put a second pebble or bit of wood on the ground to denote the new location. Finally, draw a straight line in the dirt from the first marker through, and about a foot past, the second.