Black Spot is spot on.
Try continuing to work on those thumbnails with color (still in a thumbnail size painting), it'll open up the door to color-composition.
If you add more hues to the WIP guy's face and his dragons, it'll make them seem more life like. If they are to close to one hue, they'll seem more like painted sculptures. Red in the checks, nose, and extremities - blue in the shadows, especially the chin for facial stubble.
Check out how Mike Butkus uses color, especially the exaggerated color in the very organic zombies.
I love to energy of the flailing dragons, and the head studies look very promising.
Keep up the good work.