Digital art - Critique/help needed

[Pukahuna]

Hi, i'm making this digital art, it's just for pratice, but i'm struggling with the same problems I have on every digital art I do, so I decided to create this topic . I can see that there are many problems on this work, but I don't know exactly how to fix them.
 


These are some things i notice that are bad, but if you have something to point, please do
  -Even if I work many hours in the same drawing, it still looks unfinished and weird (The rocks and water on the bottom), how people can do such a clean looking art in just a few hours
  -The colors are very weird, monochromatic and flat, some of this I think is because the habit of working with low color count pallettes in pixel arts
  -The background have no depth, I would like to make the ''world'' seem huge, but looks like everything is near the character
  -The shadows on the character looks like dirt, and he is not merging with the backgorund
  -I don't know how to texturize things that are far from the view, the rocks near the water on the left are an exemple of that
  -Anatomy is not the best too

If you have some tips for me I would really aprecciate, and if someone have the time to make an edit over the draw to point out the solution of some problems it would be my dream
Bigger version of the image: http://imgur.com/a/LRD0a

Thank you and sorry for my bad english

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Edit: Changed the background and colors a bit

[Mittwoch]

Okay, I am not 100% sure how qualified I am to help you but I wanted to try anyways. I think the main problem is that your shadows are all very grey. The picture lacks an underlying "tone", basically a color that sets the mood. I think you tried to get some red in there, but you need to amp it way up. Especially in the darker areas, the colors need to be stronger.
I just brushed over it a little bit to show you what I mean, I hope that's okay.



If you want the mood to be more cold and green-ish that could be tricky because that will always cause skin to look a bit sick or like the picture was shot unterwater.

Sadly, I can't help you much with the background, I have my problems with that too, sorry.
The river in your second picture already looks like you're heading in the right direction, though. At least in my opinion.

[LarkoftheRiver]

What size canvas do you work in? I think I know part of your problem, if you work in smaller sized/are posting your art at the original size.

This deviantart tutorial pretty much sums it up better than I can: http://fav.me/d57reew
I've been wanting to do this type thing in my art too. Basically, always work in a large canvas, then when you scale it down for posting, all the imperfections of lines, etc, will all be scaled down too. Most of the time they won't be noticed. Its now really smooth lineart is created.

In my opinion, the river looks really nicely refined.

I like the colors Mittwoch added too. I would even bring out more blue than they did. I have no idea what sort of mood you wanted to go for, which would effect what colors you want to accent. I think a sharper blue/red contrast would look really striking and awesome here though.

[Pukahuna]

Thank you Mittwoch and LarkoftheRiver for the tips, I changed the colors a lot, and scaled it down, it was about 5000 pixels wide, now it's about 1300, The video really helped, I increased the sharpness and now it's looking much better.
The character and the background still not merging really well, but i'm satisfied with the result