Sirius and Cyron Screenshot

Let's get to work, shall we? Pros and cons and all that good stuff.

Starting off with the cons this time.
First off, that anatomy could definitely use some work. I'd suggest looking at otter skeletons for form and full pictures for the way the fur falls. The nose and mouth are a bit high and the right eye is a bit too small compared to the left. The ears are a bit too big and Sirius's chest is too small for his head. If you were to go more realistic, otters have pretty streamlined bodies that are made for swimming which is why they have smaller ears and the placement of their shoulders. Both Sirius's and Cyron's faces seem a bit flat. That could be fixed with a little line above the muzzle to tell dimension and give the shading a bit more of a feel.
Speaking of shading, you use only two colors. The flat tone and the darker one for shading. This makes your drawings look flat. You need more tones for your drawings to gain dimension. Two tones won't always cut it. Try using value scales for each color you use with the flat/"main" color being in the middle. It will give your drawings so much more of a texture, dimension, perspective...in other words it looks pretty. SAI has many wonderful features. You just have to figure out how to use them! X3
Ok now here's something that really bugs me. Cyron's feet. And since there's snow on the ground, they'd sink in. But in the drawing, it looks like he's hovering above it all. Depending on the amount of snow on the ground, his feet would sink in because of his weight.
Sirius's bandage has nice shading but the way that the wound shows doesn't quite make sense. Some parts would be wrapped more thickly than others and some parts overlap. The way the blood soaks through seems to ignore that. I know that some parts of a wound bleed more heavily than others but it would take longer for blood to soak through a bandage with more material than one with less.
Last and most importantly, the background and the lineart. You use MSpaint a lot. I've been to one of your streams before. While that can be a good thing, it can be a bad thing aswell. You're doing all the drawing and coloring in MSpaint and then going into SAI and blurring the shading. That isn't good. I can tell because when I got SAI I did the same thing. You should pick a program and do all of it in that one. It will look a lot nicer, trust me. MSpaint is all pixelated and has no pressure setting so no matter how much you click your mouse and press on your tablet, it will end up in that color. SAI isn't like that. The pressure has a lot to do with the end result so things have a softer feel. When you put something with a set pressure against something without one, things can get messed up really quickly. The lineart looks very stiff and flat even with the shading and the tree is a bit of a mess because it also looks like it doesn't belong compared to the softer background. You're using blur too much on the background as well probably because it's something you can't get with MSpaint alone. I'm being as honest as I can without sounding rude. And the only way for anyone to improve is to step out of your comfort zone and try something different.
Let me help. I can show you how to use SAI if you are willing to listen and watching you struggle with it is driving me insane.
The color palette is a bit of a mess. I can't explain how to fix it. I don't know how to.
I'd also recommend using reference photos for the background. It just helps because it does.

I'm sore, stiff, and tired as hell right now. Just got back from a 4hr horse ride. So if there's anything that doesn't make sense, note me for clarification.