I love the blending of effects with the render, and the different shades between foreground and background. My advice is to add some stronger lighting and depth, as well as more colours, as it does seem fairly monochromatic at the moment and could benefit from some stronger blacks/oranges/yellows.
If it was me, my next step would be to burn around the edges, and dodge the light around the render and some of the background on the right of its head. Then tinker around with colour adjustment layers.
All in all, awesome tag.