Okay, so maybe you already know this, if so, just ignore this post. I can't remember where I first heard about this method myself, but I thought I'd share for those of you who are as of yet uniformed. This is especially helpful when hanging groups of art together.
1) Measure the size of the frames you want to hang and cut pieces of craft paper to the exact size of the frames.
2) Using masking tape, place the cut pieces of craft paper on the wall in the location you want to hang the pictures. Then adjust until you have the exact spot where you want to place the wall art.
This step is great because you can play around with the wall position of the various pieces of art until you find the perfect spot and can actually see exactly what it will look like before you've hung a single picture.
4) Measure the distance from the top of the frame to the top of the hanger on the back of your frame.
5) Take that measurement to draw another line at the top of the paper. This time draw a horizontal line.
6) These two lines should cross. Where they cross is exactly where you want to hang the picture. Take a nail and hammer and tap gentle to create an indentation in the wall where the two lines meet.
7) Now you can take down the craft paper, hammer your nail into the indentation point and hang your picture. Simple. And no unnecessary holes in your walls! Tada!