This is a fun process of creating and finalizing a concept. That can evolve into more elaborate rendering. But as an early part of the concept is very practical. I like and I've apply this in my concepts
01- initial process, gesture and pose of character
02- use the base drawing with reduced opacity and clean the drawing .
03- basic silhouette and shadows shapes.
04- initially only solid shapes, and ending with shadows more details and lights spots.