Cardinal directions such as north, northeast, west, southwest, etc. These two constitute a base or reference line. Ancient peoples figured this out long ago. Fortunately, in the Northern Hemisphere, Polaris remains fairly constant. Tables of different astronomical observations are published in an ephemeris .
Different months are easily obtainable.
GPS units accurately determine north. How the magnetic compass works . Please review Appendix D, pp. 606-612 in Map Use . There are a number of different types of magnetic compasses from the very basic and simple to more complex types made for different types of work in the field.