Looks nice. I like those weeds in the water. Anyway I have a couple of tuts you might want to look at one could help the lighting in this image, the other is based on volumetric clouds

http://www.renderosity.com/mod/tutorial/index.php?tutorial_id=2281

http://www.renderosity.com/mod/tutorial/index.php?tutorial_id=2279

 

I think the picture could do with some framing from foliage in the foreground

Take a look at this image to see what I mean

http://www.renderosity.com/mod/gallery/index.php?image_id=957998&user_id=42108&member&np

http://joevinton.blogspot.com/