Which Way is North?
If you have a compass, getting your bearings is easy. Unfortunately, if you were prepared enough to bring a long a compass, you probably were prepared enough to not get lost. So what do you do when a compass isn't at hand? Well, there several ways to figure out which way is north, unfortunately they all include a level of inaccuracy so I suggest using as many techniques as you can.
Using the Stars to Navigate
The biggest drawbacks with relying on the stars is that you can only use it at night and the sky has to be cloud free. Under the right conditions, you should look for the North Star which is the last star in the handle of the Little Dipper. When you walk towards the North Star you are also walking north. To find the North Star, draw an imaginary line between the two stars at the end of the Big Dipper's bowl. The distance to the North star is about five times the distance between the two pointer stars.
Alternatively, you can look for the Southern Cross which is a group of four bright stars that form the shape of tilted cross. Again, using your imagination, extend the axis in a line 5 times its actual length. The point where this line ends is south. If you can view the horizon while doing this, draw an imaginary line straight down to the ground to create a southern landmark.
Using the Clouds to Find North
For the most part, weather patterns move from the west to the east. Thus, by observing the direction in which clouds are moving you can infer there direction that marks north. Be warned that this rule of thumb can break down in mountain regions.
Look for Moss on a Tree
Moss grows in certain environments. These environments tend to be shaded and moist. As it so happens, the north side of tree trunks remains more shady and moist than the south side which can make for a good indicator of direction. Of course, in some dense forests you'll find moss growing all around the tree trunk.
The Worst Case Scenario Survival Handbook - Travel by Joshua Piven and David Borgenicht