Had some time an made an edit:
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The first thing I did was to fix the anatomy and tried to create a more natural, believable stance.
It's hard to explain colors, but try to keep them meaningful. You had 38 colors I think, and I got my edit down to 15. I would suggest working with other palettes til you get the feel for how they work. Another words, force yourself to use, say... 16 colors only and adjust those. Your palette has good contrast overall, but some very similar colors which don't add anything. I learned more about color from doing fixed palette collaborations and doing edits.
Try to create definition by paying close attention to lighting. And think in terms of pixel clusters and limit the use of single pixels.
And don't be afraid pf pulling things apart and shifting things around and redrawing parts. This goes back to my first sentence about fixing the anatomy. I separated, stretched, redrew, twisted, etc. before I did any details, then I pulled it apart again, and again.
I hope my advice was helpful, I'm no expert.
Also, you had a weird 66% or something scaling on your image. Generally it's preferred to post original size.