Very nice maps! I like the gradients on some of them, although I can tell you need to be careful or it affects readability. I also like the texture/pattern you use on the background. How do you make that?

There are a number of tutorials on the site that explain how to use feathered selections and clouds/noise to randomize mountains or the edges of continents. They also work really nice for creating realistic rough cave walls. You might try one the cavern map and see how it turns out.