I'm doing this today since I wanted to leave a critique on this but had no time yesterday. x)
I think this picture looks really nice! The many glowing effects, they do leave an impression. I like the emotion you put in this. It's a personal piece and it shows. It's a strong picture.
There's a few things I'd like to point out.
Anatomy-wise, the fact that the anatomy isn't realistic doesn't bother me much. But somehow, the proportions are off so the body doesn't quite look in balance to me. For example, the head's size is good comared to the body, however compared to the back legs it's really small. I think you should leave the belly more visible and make the back leg part thinner.
I would also either add more of a muzzle, or place the eyes higher up, since the face looks rather small.
The legs may look thick but that's not much of a bother actually, and Flareon are stocky creatures so it isn't really a bad point. The tail is huge but that's not too much of a problem either.
Now, for the shading and highlighting, there's a lot of stuff that you can play with to make this look even better. c:
The stones on the ground look nice, and so does the shiny floor in between the stones. However, the stones imply a 3D structure while the floor in between would be flat. Since the stones are higher up than the floor and the floor is so shiny, they would leave some kind of reflection on the floor, or shadows at least. It'd make both the stones and the light source stand out more.
I'd also use heavier light and shading for the stones, since there is a really bright light source yet it doesn't stand out on those stones very much. Still, I like this idea for a floor.
As for the shading on Flare herself, it's nice, but I feel like the light on her should be more heavy. She's producing some bright light in there, and it's very close to her, so it should show on her fur.
I really like the effect of the light swinging around her head a lot. The pawfire is nice, too.
The shaded parts look nice, but I would've added more light on her back legs, I feel like the light would reach farther on that part.
I also feel like most of the unshaded parts of the tail should have some shading anyway, since it's unclear why there would be light on those. I would blend the tail shading more to create more of a round shape, it looks a bit flat this way.
Finally, I would add some kind of blueish shine on Flare at some parts, to reflect the blue of her surroundings, and to make her blend in more with the background.
I might critique a lot but I actually still think this is a good artwork. xD It's not perfect but it still is a great piece, and I sure do love the emotion in it - most vents don't make it into full pictures like this one.
Keep drawing, you're doing great and you'll only improve more if you keep it up like this!