A great picture that works very well. The colours are lovely and the shading on the scales works very effectively.
I would have liked to see more shine to the (guessing here sorry if im wrong) the metal armor to show how it is a different texture to scales on the body.

I would have also liked to see more detail in the background, a little more shading on the trees and mountain i believe would make for a greater impact. Also softer shading in parts especially with the shadow.

The anatomy of the dragon is very good i especially like the legs and feet, and the flowing skin on the wings. The only thing i did notice is that the head looks a little small.

all in all a well thought out picture that shows a lot of work having to been put in to it oh..and before i forget i really like how you have done the flames it really gives the fire a very different texture to the rest of the image.

Well let's see.
First off, I'd like to say it's a lovely piece! At first glace, the picture is lively and full of colors and action. But after studying it, I've noticed there are some minor things you could improve on.

To start with, the first thing i noticed was the head. In comparison to the body, it is way too small. That, or the body is too large for the head. Your anatomy is descent. Although the overall body of the dragon looks very stiff and pointy. Also, the feet look good, but the they're all facing the same way. Perhaps if you turned the front left leg (his right, the one farther from us) slightly outward, he wouldn't seem so tense. The scales give him great texture! I noticed you did slightly, but say around the head and legs, make the scales get gradually smaller. Here's a good example: [link] Also, leaving slight spacings between the scales might make the body look more flexible and movable.
It would give you a slightly different texture, and it's completely optional. Here's what I did with that: [link] The wings again looks very pointy and rough. Try rounding the spikes a bit more (the turquoise ones.)
Also, if you'd like the wings to have a slight bit of texture, try using some subtle veins. The chain on his legs needs to stand out more. I kind of just merges with the shadow.
Background- Looks good! I've just recently learned in the last couple months that backgrounds are very important. They can make or break a picture. The rock he's standing on looks great! Adding the shadow really helped. As for the sky, I'd spent a little more time coloring that in, it looks unfinished, even with the clouds. The distant trees are a nice touch. Although personally for the brighter green, I'd use a more natural looking one.

Hope that helped.