I don't have much in the way of artistic ability. I think we'll all agree to that after looking at Exhibit A:
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By following tutorials for a tool called Wilbur (there are a number of them hereabouts), I was able to get Exhibit B:
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Still no trace of artistic ability, but it has some (very) basic technical merit.
The ideas are simple: make a mask for the coast, one for the mountains, and one for the forests. Combine the coast and mountains as shown in http://www.cartographersguild.com/sh...ew-Found-Lands, then raise the forests up a little and add some noise to get some texture on them. Save a lighted map from Wilbur. Make a river flow map and save that, too. Finally, load up your color base in your image editor, load the river flow, and add the lighting map using your prefered blending mode (multiply is a little dark, but it works well).