celestial navigation is 4000 years old
If you see the night sky every night (without distracting screens), the shapes became kind of familiar.
So now you can see why Polaris will not always be aligned with the north spin axis of the Earth - because that axis is slowly changing the direction in which it points (precession)! Right now, the Earth's rotation axis happens to be pointing almost exactly at Polaris. But in the year 3000 B.C., the North Star was a star called Thuban (also known as Alpha Draconis), and in about 13,000 years from now the precession of the rotation axis will mean that the bright star Vega will be the North Star.But of course if you really know the dark sky well, there are a lot more points of references, you will remember what constellations will be where at what time of the night at what season. Or where the moon is, etc.