Ok, the left one seems to have some details for now. Let's take care about the center and the left one. I'm using only that brush, we've started with.



















Shadows can be done with any king of brush with opacity or Flow set to 1% - 4 %.







I've painted all this on a separate layer so now I can move, transform and do whatever I want and it will affect only my building. So I will drag it a little bit to the bottom and pain a roof or something to my center tower.