I wanted to do a 3D version of the Kowloon Walled City. Since I'm not particularly mad, I'm attempting just a small courtyard with a tree on one wall.
I'm working from reference images and this is what I used to create these basic templates:

I'm trying to create modular pieces so that I don't have to create massive amounts of unique geometry. The following images are in order of progression. That said, here's what I have so far:
BASIC ROOM

WINDOWS ADDED

MORE WINDOWS

AC UNITS AND CLOSE-UP

PROPS

I have a lot of work ahead of me but it's a start. I'm still trying to figure out how to do modular architecture so any tips would be appreciated. I'll be working on textures and my tree next.