Wow, this picture is stunning! All of your pictures are wonderful but this one in particular caught my eye
I love how the shading you used made the hair, fur and clothes look real, but still maintain that cartoony vibe. This goes for the adorable faces, too: they contain realistic elements, but the light-hearted style really adds to the overall happy mood of this painting. The highlights and shadowing are all just lovely.
The expressions are perfect: I love especially how you did the reflections in their eyes! It really makes the picture seem like it could really be happening. The composition is spot on, and I particularly like how you drew them in a realistic camera pose! You can see the fox's arm stretched out, possibly holding the camera; a cute and clever technique to make the characters appear to be in a real situation.
Overall, I don't think there's anything you could improve with this! It's a wonderful portrait and I think you should be very pleased with the result!