Excellent job on the house! for the giant, some tips that can help achieve the Looming look to it, whether you used a clipping mask or just erased off the unneeded parts of him I would recommend using the magnetic or the polygon lasso tool and just go along that mountain edge as closely as possible. he'll appear like he's behind the mountain there.
I would bring some of the color back with him just a little. another great method for showing scale is maybe grabbing a photo of some flying birds and put them in the scene really small around him.
