Hi,
The obvious first thing to improve, is the texture repetition of the facade. You can use CoronaUVWRandomizer (CoronaMappingRandomizer) map to achieve this randomization. The full how-to article is
here.Beside that, keep in mind that eve if the materials are perfectly set up, the lighting is great, the render can still come out not so good, as a very important aspect of the perceived render quality is the composition of the frame. Think about it as if it is a real project (and a real photo). How would the front yard of the house look like? Does there need to be a walkway or not? And other aspects as well. The best thing here is to observe and check many many references (both real photos and renders of others) and keep improving.
From the quick things you can do is to place a direct light (Sun) comping from top right - this will give a contrast to the facade and the whole architecture of the house and make it more dynamic and interesting. Then you can work on the materials and texture. Then you can add some trees/shrubs in the foreground and make the composition more interesting.
Hope this helps.