I like the clouds - there is a "detail" to them that looks really nice. Great work!
The wood on the house looks nice as well. I am assuming this may be an image map?
However, the ground is missing "something" and I'm not sure what at this point. It looks more like a 100% flat surface with sand colors swirled on them, rather than true dusty dirt. It may have something to do with displacement and reflectivity that needs to be re-tweaked. The stones also look too regular and too "polygony", but I know how difficult it can be to keep them from looking that way.
Also, the foliage looks a bit too regular. Is it just the same model, or multiple unique models of the same plant? I've found having a minimum of 3 unique models in a population really helps keep things different looking, and the more the better.
I think it could also use some soft shadowing and slightly higher GI settings.
I know this was more of a quick render so I hope the above doesn't sound so harsh.