The basic thing I'm currently working with was nicknamed "squirkles" by the respective artist I'm taking notes off of. A mixture of circles and squiggles mixed together to not only be used in shading but for textures as well. The closer the squirkles are the darker a tone you can get, and the farther away, the lighter a tone is. Mixing them together can create very convincing textures. I think in the next thing that I draw, I'll focus less on a totally black picture and more how light bounces off things.