Endriago

As an old roleplayer I could never resist a dragon. You asked for critique in the forum so here goes.
Photograph your image in daylight but dont have the sun come directly from behind, the image is too dark. I can hardly see where the dragon starts and the background ends.
Use more contrast. Use a lighter colour than the colour of the dragon to give the edges more dimensions. Take a close look for ten minutes at a small dark object with a complex shape you can hold in your hand and shine a small lamp from the side. You will quickly understand what I am talking about.
Dont just leave your sketch lines so bare. Use them again by adding a dark colour to one side and fading it out.
The sketch is good, I just think you need more time getting to know how to deal with the paints.