Mirrors are such a simple invention when you break it down: a piece of glass with silver coating on one side to create a reflective surface. Very elementary. But consider the difference that grayish layer makes: literally the difference between a window to what is beyond and a reflection of what is within.
Mirrors began as utilitarian and have progressed to become fabulous design accessories. There are a few good guidelines to follow when using mirrors as decor embellishment rather than simply functional. There are a million styles and sizes and frames for mirrors now which makes them a perfect addition to any room whether you need them to duplicate an image or simply add light and sparkle.
Hung opposite a window, a mirror can throw a lot more daylight into your room (a fantastic option for rooms with north-facing windows that get limited daylight, like in this room below that I designed). It's almost like adding another window to the room when the outside light is reflected back into the room!
Hung opposite an exquisite piece of art or an interesting piece of furniture, it creates a duplicate view of that wonderful adornment. Placed above a fireplace mantel they add a little more sparkle and drama to that focal point.
Large mirrors on a wall will add depth to your room; hung ceiling-mounted they add height (both are great tricks for small rooms!). As shown in this photo, I added a large leaning mirror to add depth to this dining room and bring some of the outdoor light and greenery inside.
Are there any places a mirror installation doesn't look great? Well, just one in particular. A mirror hung opposite a blank wall in a small space such as a hallway will look void and lifeless since it has only "nothingness" to reflect. Even an extraordinary frame will look lose it's "wow" factor if the mirror within it has nothing interesting to reflect.
Look around your rooms at the walls that seem lifeless, flat or unadorned and consider what a mirror can do to change your view!