These are some old practice sketches I did a few years back on my iPad, testing out Tara's vine charcoal brushes in Procreate: https://dizzytara.gumroad.com/l/cYZZT.
Great brushes, with a lot of tone and texture control. I don't get a chance to use this style very often but when I do, I have a lot of fun.
As for my own process, for these I will start with a black canvas, loosely sketch in the subject with white pencil and then do all the toning with white charcoal to keep it moody and dark.