Also check out Jonathan Roberts, the artist of (among other fantasy maps) the official map folio for the Lands of Ice and Fire/Game of Thrones.

His blog is full of both granular and general advice: http://www.fantasticmaps.com/

And his article in the Kobold Guide to Worldbuilding is my go-to reference for using cartography as a worldbuilding device: https://www.amazon.com/Kobold-Guide-Worldbuilding-Wolfgang-B...