I love the blue bits of lighting on the dragoness's legs. They are clearly visible and really enhance the piece. I also LOVE the blue one's coloring. He would be stunning just being the deep blue that he is, but he is dazzling with the yellow red pattern. Fantastic shading, and the wing size looks realistic. I especially like the shading on the dragoness's spikes and head plate. The anatomy is also flawless. I love the blue one's hands/paws. Especially on the hind legs. Also, the spines on both dragons are perfectly placed for the most effect.

But i think there is room to improve on some parts. The rock/mountain in the back round on the lower right for example. I think the lines could be a bit more subtle, and it would look cooler if they branched off, like cracks. The clouds could use improvement, but i know that they are really hard to do. The limbs could connect a bit more smoothly to your dragon's bodies, although its not so noticeable on the blue one.

All in all, its a fantastic piece! Good job!