The most important thing I've done here is just adding line weight (and blacking out a few small sections to help clarify my leg-forms and reduce a lot of the clutter going on). At this stage in the drawing, you're going to have a lot of overlapping lines vying for your viewer's attention. You want to set these out in a sort of hierarchy of importance, so your viewer ultimately knows what to look at first. As we covered in the last lesson, your first tool for achieving this is simple line weight to clarify what exists in front of what. Second is filling in areas with solid black to help another area of white to really pop into view.
You'll also notice that for the back legs, I added some very simple, straight hatching. Straight hatching on a rounded object is usually a no-no, because it'll flatten your form out completely. In this case, that's what I want. It's a design choice to help push those legs back in terms of importance. I want the viewer's eye to glaze over those details in favour of the legs closer to them.