This one, drawn today, caused painful hours of hand cramping and use of many erasers. Seriously. I lost count of how many times that I redid those feet!
This is very well done! I love how you did the crest on the back. I also love the underbelly, it looks very well realistic! The texture on the wings are great, and have a lot of dimension to them! The proportions are mostly correct, but assuming this is the average dragon, the wings and legs should be bigger. Although the wings are large, they would need to be quite a bit bigger to fly. You could accomplish this by extending the upwards or making them longer. As for the legs, they would need to be larger and more muscled to sustain a dragon as big as this one. Although it'd be able to stand, it would be with relative difficulty. Also, as a general rule, the back legs are larger than the front ones. This is because the back legs are usually used for support while the front legs are used for utility. Other than those things, the drawing is really good, and I'm looking forward to seeing you improve!