I have a small suggestion, the colour of the windows of your house shouldnt be light blue unless they were reflecting the sky. They should be some mix of the house interior colours and the grass in my opinion.
About adding textures: I think thats something you should decide, the piece is currently quite pretty but perhaps adding well made textures could make it into something very remarkable. It would also probably challenge you which can only lead to you improving your pixeling skills 
Actually, most windows should be completely transparent, so you should only see the interior(of course, this depends a lot on glare and other aspects...). There's a problem with that though, and that it just doesn't read well most of the time. Most people use light blue because it indeniably reads as a window to everyone. Especially with windows this small, where not a lot of interior is going to be able to be seen, it just won't look good, I don't think.