DeTeEff

Open up good city sections in DR and study them.

They're often angled skybox walls (making the area squashed polygonal) with portaled kiss points out, a surrounding layer of tall buildings, and on an angled z-axis ground. Those features alone will get it started off looking natural and lead to interesting architecture.

I don't understand this: "making the area squashed polygonal"

And "angled z-axis ground" Do you mean different heights of the ground?

Sorry. For "squashed polygon", I mean if you're looking down at the street in DR, there are like 6-10 skybox "walls" of different lengths so it looks squashed into an oval. It instantly gets away from 4-wall boxy. And by the ground, yes I mean different heights, but mostly I mean the ground is sloped with patches & stairs. That's what I learned from looking at great city missions.