Pretty cute, I like this. Quite appropriate for the cold winter in the US and Canada right now. It's actually unusually warm in where I'm living right now- quite weird.
It's very nice to see fanart with a touch of humanity- and I see the direction of this artwork pretty clearly- I just got a few suggestions here and there
I see that you used a similar shade of magenta for both Spike and Twilight. I understand that they are both purple, but visually it may look like they are 'clumped' together. From the looks of it Spike is in front of Twilight. When it snows, the visibility is often very low- I think you could take advantage of that. Basically, what I did in this Photoshop edit is that I added a translucent layer of white over Twilight, which indicates that she is further behind in the snowy atmosphere. To make Spike pop out more as well, you could also create a shadow on the scarf and front legs that is casted by by the head. If I'd work on it further I would also soften the tones of that shadow to create further depth as well.
As for the colours- I like the colour choice of complementary colours with the yellow egg/scarf and the purple of Spike and Twilight. But to me the colours seem a little bit too oversaturated- I'd see why though- because that's pretty much the design of MLP so there's no avoiding the brighter, more technicolour range of colours. I guess I would still use those bright colours, but do so sparingly- probably in key focal points like Spike or Twilight's face. I might reduce the saturation for other parts such as Twilight's hair or Spike's wooly hat and egg. Therefore the viewer's attention would be directed at the correct space. Honestly, figuring out the colour and lighting for this piece would be slightly difficult and ambiguous due to the snow- and everything being showered with white light which doesn't help when it comes to the choice of colours, so I don't really know.
But anyways, this is still a great piece of fanart and it made my day- it captured the relationship between the two characters pretty well and it's very relevant to the current weather. Really hope this helped and keep up with the great work!