/ic/ - Artwork/Critique

I started trying to learn to draw this past July, and I'm not really sure if there's any specific exercise or resource material I should be focusing on right now. I've just been drawing from reference for the past couple weeks, and while I'm happy that I've managed to keep practicing, I feel kind of weird just doing that without dedicating more time to studying materials, and I don't want to stagnate. I tried drawing this from imagination last night/this morning. I know it's really basic but feel free to tell me if there's anything specific that I should be trying to study right now.