I would probably just push the lighting on the white centaur a bit more. Just a little bit, not to much. That way he pops out a bit more. Also, try to break the silhoutte of the centaur beneath the white centaur's hoof with a bit more dust to help give it a better sense of depth(I recommend doing this in photoshop first to see if you like it or not). Loving the way its going Emily.
Very good! I really think you did a great job underlighting the dark centaur. The dark centaurs furthest back leg closest to the side of the page could probablly be given the tinies highlight, since his joint his blending in with the background.Just a suggestion. Really great job thoguh, it looks great!
Love the lighting on the dark centaur's shoulders but I wouldn't mind seeing that lighting drift down the to the back to define its shape just a tad. Love the palette.