I started out in hope to protray some sort or lighting intuition but after 5 mine of this crap I stopped and gave up becuase I started way to small. I really need to read a book on lighting and shadows becuase i really suck @ this stuff.
i had no direction just painting aimlessly, maybe thats why.
When in doubt, just use sculptural lighting. That just means, Make things dark toward the edges, and crevices, and light toward the center, and full areas.
<edit> here’s another suggestion,…try starting with a black, or dark gray canvas instead of white. That way, your shadows are already in there, and you can just brush in the midtones and highlights.