Hanging pictures straight is a bit difficult as it is, but when we’re talking about two screw or two nail frames, getting them exactly right can be downright frustrating. Fortunately, the folks behind the DIY site It’s Overflowing have a solution for those of you that have a bunch of these tricky frames laying around. Just use a piece of painters tape (or any tape really) to mark the distance between the two holes, and then use the tape to line up and level the holes you drill. Voila, picture-perfect picture frame hanging.
Simple DIY: Creating a Window-Pane Mirror (via Lifehacker)