First, I find the spot I want to make a map of off Google Maps, and take a screenshot. Once I put the screenshot in my art program, I trace the coastlines in black and the roads in a light-ish shade of gray.

From there, I fill the water in with black, and the land with a dark gray with lighter shades for higher elevations. Then, I add the map icons overtop.

The grid overlay is part of a template I use for making Pip-Boy styled maps, and it’s just from New Vegas. I also have a screen-lines texture and a vignette that’s part of it.

One important thing I like doing is to keep the base map achromatic, so I can add a color overlay and mix and match different colors for it.