A lot of people liked a certain area in a recent drawing I did, so I thought I'd make it into a pattern, with a little discussion about shading/shadows. You might also want to see my post about tangle enhancement Threedy.
Another question I often see concerns knowing when your work is finished. The answer to that is going to differ for everyone. But one thing I've learned for my own process is that if I look at my work, and it just seems 'right', however ambiguous the reason, I stop.
I had intended to add a lot more tangling, but this just felt 'finished'. I think I like the contrast of the simple skeletal line work next to the heavily textured, shaded areas.