looks good to me 
*you need more colors and values grading for the 3d elements to match the plate more and of course some more textures (I assume some 3d elements aren't textured yet). btw you're losing the bounced light effect on the 3d elements ;)
*Be careful not to make things look too perfect because in real world, everything's not perfectly placed according to perspective, so i guess it's okay if some elements don't perfectly go along with other elements. right now they looked perfectly straightened and elements are too visually organized, or what the industry called as "too clean" (not literally clean). sometimes, just a hint of an element is "more" than completely showing the whole element :)
Tip: To be able to (however) accurately tell the imperfections, imagine how the people
will live in this environment. Their flaws will determine the flaws of the world they
live in. :)
*and one last thing, i noticed that your 3d elements have lots of greens on them, might as well have some of that greens on the plate too, for a more consistent looking scene. or you can do the other way around, whatever makes you happy. (on the house itself, not just on the roofs)
Hope that helps :)






