The line weight in the hair is doing most of the work. You varied pressure enough that it reads as volume, not just outline, and that's not something most self-taught artists figure out in the first year. If you're looking for a next step, consider where the darkest darks want to sit. Right now they're spread evenly, but massing them in one zone (under the jaw, maybe, or deep in the hair) would give the whole drawing an anchor.

The no-training path is real. I shot landscapes for three years before I took a single workshop, just went out every weekend and learned what didn't work. If you want eyes on specifics, posting the drawings usually gets more useful feedback than asking in the abstract, people can point to what's working, what might be next.