I thought I would start a series with some common design problems, and show the solutions. One thing that I instantly notice when I enter someone's home, is their artwork. People tend to hang their art way above a sofa, I like to think of them as a grouping, so your eye needs to connect the two together.
Here are some simple rules to follow, but of course I just use these as guides, I go with what feels right for the space.
Art should be hung 6"-8" from furniture.
When hanging two pictures stacked, treat them as one piece with the center point between them being 56"-60" from the floor.
To determine what space to put between pieces, either go with the matte size or 1"-3" between pictures.