Trying to draw realism with an animal takes time and lots of practice.
I think you're headed in the right direction on this piece but it needs some tweaking. Look carefully at your reference and you'll see some changes that need to be made to make this come to life. Check the eyes first. They aren't oblong as indicated in your drawing. The eye itself is round, the fur and skin around the eye provide shading to give it shape. I think the muzzle may be too long for the face. Check measurements constantly when setting up your drawing to ensure that features are in the correct place. An easy way to do this is drop imaginary lines from a feature, such as an eye, and see what lines up with it, so you get the correct proportion.
The most obivous thing that I see is lack of values in your image. You have some darks on the tips of the ears and paws, but the rest is very monotone. You need to introduce shading into the fur but adding layers of graphite. If you're aiming for a realistic animal, this is a slow process. Don't rush it.\
I have attached a sketch I did of a fox to give you an idea of what I'm talking about in terms of building layers, eyes, etc. The sketch isn't complete but may help a little.
The key to all drawing is keen observation. Go with what you eyes see, not what your brain tells you and you'll do fine.
Click to view attachment