Villa Concept

well the windows do look like reflective metal. but my bigger issue was with the overall gamma and color of the image. you are getting a lot of green reflection on the underside of your building. if you go into the grass material, there is a way an override material for the reflection color. meaning you can have the green grass reflect a white color onto the underside of the building. then you can also reduce the lightness or saturation of your grass. i took a shot at editing the image. i made my adjustments while trying to keep the very 'bright' feeling i think you were going after.