Absolutely love dragon character, hes so cool! For design I added ideas of what you could do like add something on his waist or make the jacket/cape he's wearing over his shoulders drag on the floor and fluffier. For color, your values are pretty much the same which makes it blend together. I used the tone curve to adjust the colors a little, like making the dress he's wearing stand out from the dark cape. I recommend having a black layer set to color on top of your art so you can check as you color!