Quick edit/paintover while I've got a minute (more edits in the works, loads done, if obsolete) taking into account the advice of Tourist, Sohei, PixelPiledriver among others.

If it seems overblown compared to what you were going for, don't let that discourage you. There is some basic important stuff here to take note of.
Notice how in the edit, none of the limbs mirror each other. One leg higher than the other and more subtle repositioning on the arms and bat-wings. This asymmetry is there in your version, but it's stiff and 2-dimensional. The arms especially look mirrored, lighting included. Generally the anatomy around the shoulder area is way off so you can afford to redraw that at least.
Basing the pose around a line of action will make the image more dynamic and dragon-like as a whole, and fix the random tail placement which I'm seeing.
Starting with 2 colors per material with a large brush (>4px) as I did makes it easier to block out lighting. Here it's top-down, lighter and more detailed towards the source/focal point, darker as it recedes. The left wing bending towards the light is the exception, but that may be more advanced knowledge so you can leave it out.