Night beat me to the punch with that great edit
Been working on this on and off for the past day.
We could just do edits for you and show some thoughts on how we would do foxes. That'd be great. We could also focus on small things to critique, and leave you puzzled at the rest. That'd be great. But it wouldn't help you very much. You need to understand why. So lets start.
What is a fox?
Start from the beginning.
Foxes are a lot of things. You like them enough to know how to shape their back foot. You raise their head with pride. You spend presumably hours struggling to bring this fox in your head onto the screen. You do it with pixel art, a medium more intimately precise and close than most. You really want to draw a fox.
So lets actually draw a fox. Number 1 thing: a fox is an animal. You are an animal.
There's a LOT of mechanisms you could research to understand how a fox works. But we can start small. You don't have to know a whole lot.
Lets gently study anatomy.
I looked up "fox skeleton". Then I roughed in bones in a similar pose to what you had. The proportions are maybe a little off from the reference skeleton, to fit your vision of a fox more. But that's fine. It's not so much about exactly copying, as it is understanding. If you understand it, you can break it. So look at skeletons. This is under the foxes you love. This is why their head is so round. And importantly: This is the deepest level to see how the fluffy fur you immediately appreciate is placed. But there are a few more steps before we can start rendering this fluffy fur (or even keep it simple, as the title of your thread asks)
The basic meat chunks of your fox
Skeleton helps to understand the basic forms. These are just flesh hunks. You don't need to know all the musculature with what you have set out to do. But you do need to understand exactly what masses are under the fluff, because that's where the fluff springs from. Color coded just for seperation.
What is this sloppy thing? lighting? Volume?
It's both. From looking at your progress, I don't think you grasp this quite yet. You're all about the contours. You don't seem to grasp this "fur" you're trying to render, because perhaps you don't understand yet: it is just more fox. So here's a simplified, not-too fluffy, smooth volume of a fox. It's lit in some arbitrary game-y way. Nothing extreme. Just enough light to define where things are, and where they are separate. With THIS step, we can see how you've been approaching it. Except you add some texture on top, like it's a 3d model. It's not. It's all fox.
All of this was preperation, and now you can draw foxes better. Well, now I can draw foxes better. I learned a lot. I hope you did too. Pixel technique is something you learn incrementally. Color theory as well. But the message I want to drive home: If you want to draw a fox really well, you need to understand the fox really well. All parts. The extent of your understanding is the foundation that all will follow from. You don't even need to understand anything that
well, just better relative to the people viewing the artwork. So don't tunnel vision on the fur, or wonder about specific parts too much while ignoring others. Wonder about all of them. Until you understand where the bones are located, you won't understand how the flesh collides and how that bunches up the fur.
But you won't be perfect, and my edit isn't perfect. If you study this way too, you will find things I didn't find. Small things that contribute to selling the idea of a fox, that you can communicate in your own way.
A much shorter critique on your actual execution: Eyeburn. Ouch. Way too red. Neon Fox. Unless he's emitting light and made of fire, that doesn't make a lot of sense. Fur scatters light. It's matte, except where its smoother, and then its shiny. So in normal lighting conditions the light will desaturate the orange fur when exposed to light, and as the light is allowed to bounce around in the clumpy shadows, it will get more orange and saturated. Don't be afraid to use more colors. A big part of "fox" to me is that their fur gets darker as their legs go down. And you can totally include the dark bits at the roots of the white fur at this resolution, just understand it is the roots: so show it where the fur is facing towards the camera and the fox skin is more exposed. That can actually be a trick to milk some more volume, you're saying the viewing a plane is facing you just by adding a few detail pixels.
This might be a lot to digest at once, so if you have any questions I will always be around to answer and help.