For the 2nd sig the shadow you added in yourself was a pretty good call to make the lighting more obvious. However, the light source still feels pretty messy. The render is a little misplaced because of the purple tone. Don't be afraid to use a gradient map to set his colour correctly. The render is also not blended very nicely into the background. That's all I have for now. It's nice to see a new face that strives to improves. Good luck.