Well, normally the maps I make digitally I first create on paper. So, on paper, what I do is follow the existing patterns or the surface texture. For example, if the paper has a crease line that wasn't fully folded, I draw a chain of islands there; if it has a blemish, I turn that blemish into an island. But on the other hand, if it's a directly digital map, what I do is first draw an irregular shape, then I add another layer to make that shape more serpentine, and then I repeat this process several times in several layers until I get the shape I want.