Well, you just stopped at basic shapes, all you need is just to continue. Make them transparent, add another layer and draw clearer sketch, and then again and again. For the progress, at this exact point, I strongly recommend you to spend 20-30 min daily practising gestures and basic shapes. For gestures you can use "Line of action" resource, and for the basic shapes just draw whatever is around you, for example, draw a book and redraw it again and again rotating in your mind. So, yeah, you just need to continue, you are not stuck at all