Step 8 - In this case, I used polypainting technique. Basically, you select brighter matcap material, preferably white matcap, and start painting directly on the model.
When you finish painting/coloring your model you can start preparing for rendering.
Now, the model is posed and prepared for rendering of different matcaps for later compositing in Photoshop.
This is the final image. On the sides, you can see different matcap combinations used to create the image. In the compositing, I have additionally placed smoke, and water drops. Smoke is partially derived from photo, and partially painted. Water drops were painted in Photoshop.