To add architectural character and "space" to a small home, consider arched mirrors. The arch shape alone is uplifting, drawing the eye upward along the curve. Arched mirrors create architectural interest even in rooms with none and, of course, the mirror's reflectivity enlarges a space. Here are a few examples:
Our favorite example is this one from Ballard Designs. The Amiel Arch Mirror ($699) is oversized for big effect and brings space, light, and detail to the corner of this room.
In the second image, a large arched mirror from Pottery Barn ($249) mimics a window opening.
Arched mirrors don't have to be huge or window-like to have an impact. This highly detailed dresser-top version in the third image still lends texture and an architectural quality. From Graham and Green (£91 -199.00).