Avoid using your mobile data plan while navigating.
Android users can go to Offline Map settings and change the "Storage preferences" to save maps to an SD card instead of internal memory. Can You Download Google Maps on a Laptop or Desktop? how to download google maps
If you'd like, I can give you more specific tips if you tell me: Are you traveling to a ? Do you have limited storage on your phone? Avoid using your mobile data plan while navigating
Note that transit, bicycling, and walking directions are typically unavailable offline. Traffic updates and alternate routes also require a live connection. Managing Your Offline Maps or foreign countries.
Use GPS in remote areas, tunnels, or foreign countries.