A primary suite should be designed around how you actually live—not simply around making the bedroom as large as possible.
Think about the relationship between the bedroom, bathroom and closet. You want enough space around the bed, convenient access to the bathroom, useful closet storage, and windows positioned to provide natural light without eliminating important furniture walls.
Large windows, like those shown in this project, can make an addition feel brighter and more open while providing views of the surrounding Arlington neighborhood.