Well, like I said, I used that tutorial. First you draw all the streets, which creates plots, in all kinds of shapes. Then you stroke the outside of the streets with a square brush with various scatter and jitter settings. That makes randomly generated blobs that then should vaguely look like buildings. After that I put a bevel and emboss effect on them to give them some depth, and some other minor tweaks. It looks pretty good, for all the small buildings at least, but I think the larger ones, like the palace could have been done manually, that would have made them a bit more unique, but oh well.