Wall sconces are a form of lighting that most people do not consider, but placing lights on the wall has the added benefit of providing an accent lighting for the wall, as well as, serving as the primary light source.
Wall sconces can provide light in a variety of places. One of the more popular places is in a hallway, in fact two or more sconces can be placed in a hallway to provide even lighting which an overhead fixture cannot do. Another popular place to put a sconce is in an entryway by the front door, if space allows you may want to place a sconce on either side of the door for a more dramatic effect. If you home does not have an entryway but your front door opens directly into the living room you can still place one or two beside the door.
When placing multiple sconces the tendency is place them in a straight line, which works well, but you could also consider staggering their height. Once place where this seems natural is in a staircase which simply makes more sense to vary the height to be consistent with the stairway that you are lighting. However, this can also be done in other places if you have a large wall in your entryway that encompasses two stories which needs to be lit, one option is to place sconces down the wall at different levels. Placing them at ill regular intervals can make them serve the role of artwork, as well as lighting source.