Martha Stewart Living, September 2008
Unfurl a length of painters' tape (ours was 1 1/2 inches wide) horizontally across a wall, making sure tape is level.
Determine nail placement for frames above the midline by measuring from the bottom of a frame to its bracket. (If the frame hangs on wire, pull the wire taut, and measure accordingly.)
For frames below the midline, measure from the top of the frame to the bracket. Use additional strips of tape, positioned vertically, to create even spaces between pictures arranged next to each other.
When all frames are in place, remove tape from wall.
The secret is to divide and conquer: Mark a horizontal midline on the wall, and hang all pictures above or below it.
The line can be delineated with a strip of painters' tape and then removed once the pictures are in place. To unify the group, choose a single color for all frames and, if displaying photographs, stick with either all black-and-white or all color shots.