An easy way to deal with shadows is to duplicate your image, then use curves / levels to make that image brighter, until the shadows are the right darkness (the rest of the house will look very blown out when you do this, but ignore that, its just the shadow tone you are worried about). Then put a layer mask on that layer, and just paint the shadows back in (which will be lighter). That way you will have the original building, and you will just be painting in the lighter shadows
Hope that made sense. Actually you made a pretty good job of taking out those shadows yourself.
I think Ivy made a good point, its probably time to strip down some of those trees and flowers
The sky looks much better now, but i think you could still afford to take out some of the bluer tones on the left of the sky? Or maybe push them further towards grey? That is being quite picky tho
I agree about getting some colour variation ionto your snow. Some greys and some hints of blue would look good i think.
Well you still have quite a bit of work to do, but its looking very promising! If you continue with it at this standard, the finished matte will look great!!