After sketching my body concept, I created each body part and pre cut them.
Then I duplicated all of it and merged it into one base and set it to be a mid skin tone color.
Then I painted all the shadows on one layer and the highlights on another. This made it to where I was able to render the entire body in just three layers total.
Now this is where the three steps back part comes in. Once that was done I duplicated the full body shadow layer into each individual body part and applied clipping masks into them with the separate body parts I created ahead of time.
This made it to where it was seamless, but now I had to clean up to do. Though it was quick work. All I had to do was magic Lasso around the fill layer and go to the shadow layer and delete everything outside of it.
All that was left was to repaint the shadow areas that were hidden behind things, like fingers etc.