Don't use nails to attach the lights. They can puncture the wires. Use clips instead
Don't run an extension cord through windows or doors. It can fray the cable and cause a fire hazard.
Don't use indoor lights outside. Moisture can make the string of lights dangerous.
Do use a stable base underneath your ladder. Contractor Steve Siera showed Inside Edition the proper way to position a ladder when you put up Christmas lights. He says you don’t want it too far out on an angle because the ladder could potentially slide. When you climb up the ladder, he says, you should not reach more than an arm’s length away, as you can slide off the gutter.
Don't stand on the top step of the ladder.
Do use power strips when plugging in the lights.
Don't use more than three sets of big-bulb light strings. “If you have a real tree, you do have to be careful. they do get really hot,” Siera explained.
Do turn the lights off when you go to sleep.