Still practicing shading... It's hard to learn how to actually use a pencil, but I'm getting the hang of it :)

Hi there, after watching various videos and stuff I think I'm getting more or less accustomed to how light works... BUT (there's always a but) I noticed there's no real indication on how to draw it "physically", a material approach or technique, only theories... So I suppose there's not some "good ways" of doing it or wrong, as long as it looks good? Experiment until we find a way that we're comfortable with? Since I use digital media too, it's a bit of a struggle starting with traditional stuff... So I had to just try random pencils I had around and some vague approach and draw some spheres... I can already see that the 3H isn't the way to go... but any suggestions on what I did? Or anything in general on how to approach it?

Some of my gestures and poses from my usual practice [from old (white BG) to newer ones (grey BG)]... I tend to add light/shadow to practice a bit about that too and learn the basis forms and shapes of muscles and body. Some times I get carried away if I like particularly some reference and spend more time on those :)