I've finished my fantasy practice map. I didn't bother labeling any cities or rivers or anything since this is just a proof-of-concept experiment to see if I can do it. I think it turned out pretty good, though. Better than I expected, actually.
I learned a few things along the way:
1.) Take note of the codes for whatever colors you use. For example, the dark green is 016e04, the brown of the mountains is 775504, and so on. Then you can just copy and paste the codes into the Photoshop palette field.
2.) Use separate layers for each feature. Absolutely essential.
3.) Using separate layers allows you to use adjustment layers for each feature. For example, I altered the brightness and contrast of the mountains without changing anything else.
4.) Rivers go on top of all other layers. On this map, the rivers were made by deleting the base layer of land so that the water layer showed through. This was a mistake. If you zoom in and look closely, you can see places where the green (or whatever) shading spilled over onto the rivers. Next time, I'll just draw the rivers on with the paintbrush.
5.) Take note of pixel size for whatever you're doing. You want uniformity. You don't want one city to be 29 pixels and another to be 43 pixels. (Or whatever.)
6.) Adjust the opacity to about 50% for the shaded areas. That gives it a more organic look. I didn't use the blur tool, but I might try that next time, too, in places where one color of shade meets another.
7.) The upper-right continent ended up resembling an upside-down vagina. That was unintentional, but an important lesson to learn, I suppose. Next time, I'll be on the lookout for unfortunate resemblances throughout the process.
8.) Make the file large so that the cities and towns don't look pixelated when you zoom in. In order to make specific areas visible on a Kindle, you'll have to have zoomed-in maps of those specific regions, and that means you need a large file to start with if you want those maps to be crisp.
Anyway, I'm calling it a success. As the features take shape, my imagination starts to conjure up stories of the land and its people. The history doesn't quite write itself, but making the map first definitely gives one a solid foundation.
And it was fun, too.