The image looks weird because everything is in focus, the butterfly is meant to be close whilst further away everything else is still crystal clear. Use some blurring either in the foregound whith the butterfy, or the background. If you can't be bothered to use too many bumps try in post rendering to put some grain effects on the trees, and grass, it will make them more textured. Oh and like Allerereureure* said, unless they're vampires, reflections would help. Cool pic though, I haven't done better with a 3D program yet. I really like the waterfall spray part.