The fine pencil is not made to fill in large, dark areas. Instead, this pencil is perfect for creating dry, sharp lines—use it to draw delicate details.
When redrawing the contours of this sketch, add some long, fine lines going in different directions to create a long fur coat.
Add a layer of hatching to create shadows and add some more dimension.
Intensify the shadows by adding another layer of hatching on top of the first.
Make the lighter parts of the coat stand out so the fur looks even more bushy.
Finish your drawing by darkening more of the details and shadows.