It's warm, it's romantic, and it's the closest you'll get to experiencing a resort vacation in your own backyard: the mood you create by simply wrapping a pergola with some string lights. For a twinkly look, go for commercial-grade M5 LED lights in warm white (about $20 for 24 feet). "They won't get hot and harm greenery like incandescents and can be left out year-round," says lighting pro Paul Gosselin. To save yourself hours of labor—or to achieve a similar look beneath an overhang—tack up strings along beams in a zigzag pattern. Simply outfit your staple gun with a wire attachment, which has a groove that centers the wire, protecting it from being punctured. Estimate how many strings you'll need by multiplying a beam's length by twice its width, then by the total number of beams you plan to bedeck.