The question I get asked the most often refers to proper art height. The center of your piece should hang about eye level, which is between 56-60". If you have multiple frames at multiple sizes, cluster them together and determine the middle. That spot should be hung at 56". Always leave 4-8" above a sofa and, like the table chandelier, keep the piece 2/3 the width of the furniture.
Frame Hanging Tips: If you have a generous amount of horizontal wall space, draw an imaginary line on your wall and place artwork above and below the line. If you want to fill vertical wall space, create a square or rectangle on your wall with painter's tape and loosely arrange your pieces inside.