Trace photos and wall art in craft paper then you can play with the arrangement on the wall before nailing in the pictures and know where to put nails. I do this for everything I hang on the walls - saves me from having multiple nail holes!
This picture frame collage is neat. I love the font on the wall and I adore the famed initial in the middle. This would take up a good chunk of our huge living room wall so my wall won't look so naked.