Using latitude and longitude is alright if you're navigating over long distances such as when flying a plane or navigating a ship. But for people using maps to navigate on foot, bicycle, or even in motor vehicles for short distances, latitude and longitude are impractical.
For land navigation, the grid system most commonly used is the Universal Transverse Mercator or, as it's commonly called, UTM system. The UTM system was developed by the military during World War I for long-range military artillery, but its practicality for any type of land navigation soon made it the universal standard for all military uses, and it quickly migrated to non-military use.
The following link will provide a document with great information on how to use the UTM system as well as some good info on GPS datums and spatial coordinate systems:
How To Use UTM