These are pretty good! I think you should focus more on starting with the basic geometric shapes of the animals and then adding the flesh and fur details. That will help with creating structure and a more solid 3D feel. The sketches where you did that have more weight than the ones where you went straight to outlining the animal. Starting with geometric shapes will also help with perspective. It's easier to understand the perspective of a box/sphere/etc. first, and adding animal details from there will make the perspective come to life!
