The lightest blue on the top doesn't work I think. This kind of clouds (cumulus) don't have transitions on the top, just a sharp white to blue boundary.
Did you use a ref?

This piece was such a shock when I first saw it in Secret Santa. One of my fav pixels ever.
Don't change a thing. Just upload it to PJ so I can rate it, max points.

(Sorry, useless ass-patting)

The thinking of [Skin-no dithering] is just a stupid shablone for me and i ignore it. I personally think that everyone should have their own style, no matter what it looks like.

It's probably your English failing you, but this could be read as rudeness...

Anyway, you shouldn't ignore advice about careful dithering. It's a common mistake of beginners to dither too much, badly, and at the wrong time. I did, too.

It looks at first like a good idea for soft transitions, but look closely at your piece and ask yourself: is it really smoother? I would particularly question the left side cheek (ours), and the nose area.
What I see there is pixel noise, without any hint of either volume, texture or shade (things which good dithering might help with, but as NaCl pointed, are difficult).

Extensive dithering in Jaeden's style works better because the colors are very close to each other, so the transitions would be smooth even without.

In any case, dithering should be applied at the end of the work, and checked after (almost) each pixel at 200% (it helps if your software allows you to have 2 windows of the same file: one large to work and one small to check).

I would advise to fix other problems before: color choices, shading, cleaner lines.
The important areas of your face need better construction (I can't explain how to do that!): eyes, nose and mouth.
Look carefully in the photo how your fingers pull at the mouth and eye.

Some areas of your face are pinker, some yellower, some greyer.

The light in the photo is very frontal, not the best option for a reference image. It is also softer than you made it in the pixel.

It's not a bad idea sometimes to color-reduce a ref, to help identify important features. The chosen number of colors can show different options, as here with 16 and 17 colors.

That's an interesting texture on the very tip of the paw, it gives a woolly fur idea.
The middle part is less convincing, because the texture direction (45° upward) doesn't look right.
The upper part is too noisy; checker patches are too large (flat) and isolated pixels are never a good option.

Killing the shadows: rather, just making a very different light source (soft, top-down) from that of the original sketch (hard, sideways). It could be an option too.