Shadow-stick method (daytime, most reliable):
- Place a stick vertically in flat ground; mark the tip of its shadow.
- Wait 15-20 minutes. Mark the new shadow tip.
- Draw a line connecting the two marks — this line runs roughly east-west, with the first mark to the west.
- A line perpendicular to it gives you a rough north-south line.
Analog watch method (northern hemisphere, daytime): Point the hour hand at the sun. The midpoint between the hour hand and 12 o'clock points roughly south. (In the southern hemisphere, point the 12 at the sun instead, and the midpoint to the hour hand points roughly north.)
Night — the North Star (Polaris): Find the Big Dipper. The two stars forming the outer edge of its "cup" point directly to Polaris, which sits within about 1 degree of true north and doesn't move through the night, unlike every other star.
None of these replace a map and compass for precision — treat them as a way to hold a general heading and confirm you haven't circled back on yourself, not for pinpoint navigation.