[Croxiin]

A few things to keep in mind:
1. Skull shape!
Different animals have different skulls and this will affect shapes such as teeth, jaws, and even foreheads! If you compare a wolf skull to a dog skull, you'll see the dog's skull has a more curvy snout and forehead.

2. Eye placement
This one usually isn't an issue, since an oc isn't typically gonna be anatomically perfect anyways, but different animals have different eye placements. For example, a wolf has forward facing eyes, because it's a predator! Deer have side facing eyes, because they're herbivores.

3. Ears
Again, not as important. When it comes to ear expression (i.e. scared vs angry) it's important to remember that if you want more emotion in your art, the ears should match the expression. It's also helpful to imagine how the ears would move if the character was real. I think the way you did them in the sketch was well, since they match with the facial expression!

4. References n' practice
I cannot stress this enough, references will be your best friend. Just look up pictures of skulls and the animal and use those as references. Here is THE BEST site for references.

I'll add on to this for more depth! Also, feel free to message me if you have any questions!