How to render 3D block maps
Cartography is one of the oldest field arts—many ancient petroglyphs might actually be maps (there are several at Twyfelfontein in Namibia).
Here is a step-by-step pictorial on how to render a cool 3D map. I did this one from a photo after a visit to Cave Creek in southeastern Arizona's Chiricahua Mountains. The biggest challenge is pulling the "box" out of the 2D image and envisioning the "cut away" part in a way that works in a 3D cube. Thanks to John Muir Laws for the tutorial in his excellent Laws Guide to Nature Drawing and Journaling.
The final step was adding the watercolor, making sure to make the farthest mountains darker and warmer blue in tone so they feel like they are receding (instead of making them green or cooler blue). Don't go crazy on the details for something this size and this simple.
I decided to add the clouds and hawk as a fun whimsy.