My today's drawing practice. Today I could spent some time on doing this drawing, which uses 's "Dark Drapery pack three" [link] as its reference. I did this in MyPaint with the characol an chalk brushes.
The folds in this image are created by black and white lines. Our brain thinks, there is something raised, because it's brighter than the other areas. And the darker parts let us assume there is some kind of shadow.
I did not paint every fold, but reduced it two few main attributes, so there is enough similarity.