Detailing the structures and scale
In a landscape with weird shapes and structures, you want to be sure that the scale reads right. For this, I just add a humanoid character, or a design that can be seen in everyday life: something like a tree, a lamp post or a car will do the trick. The eye then sees the size of this object, and can compare it with the rest of the environment. I also start refining the shapes so that they have a bit more flow and connection with each other. At this stage, I add some light circles in the background, to indicate that there’s a light source from behind there. I use a Color Dodge layer for this.