Ultimately there is a lot of testing and looking for something that just looks good. I like to jump between different shaders in order to “clear my mind” and not focus on certain part too long. Also leaving something for a day or two can be very useful for detaching yourself from the artwork. I also keep different versions saved for future review and often rollback when needed.

I recently started sharing videos from my workflows on Youtube. Here is one on procedural shading: