http://puu.sh/69IF0.png
Considering this line is a light source it is absolutely IMPOSSIBLE to give greyish tone. it should be completely white.
another thing that annoys me is the fact that you can clearly see you used a large soft brush to put emphasis on the depth.
Edit:
I took the liberty of doing some corrections and color manipulating. As I don't have the PSD I couldn't do much but make corrections but here's my version:
Before:
http://i1267.photobucket.com/albums/...nature40-1.jpg After:
http://puu.sh/69JVd.png
You can see that it looks a lot more fine-tuned now.
my advice is to look at actual photo's that don't have filters applied to them ( professional photo's of course. ) to see which colors blend together, what kind of aspects about a picture shows warm/cold colors etc.
also, a light source should NEVER be in the corner. it takes away the focus point and it's simply just unnatural.