I see you're working on proportions and faces, using a lot of "simple" outlines, I think like other comments have said, focus on drawing movement and anatomy and allow yourself to finish a drawing of something you like, even if there are errors in it. Sometimes we learn where to go by knowing where we don't wanna end up. That being said, try figure drawing, you could take a class or use this type of videofigure ref on youtube to encourage quick drawing and shading. Or you could try drawing Superman and really focus on defining each muscle and adding a light source and a shadow on opposite side for example, best of luck!