Commercial grade string lights will have thicker wires and waterproof sockets. These lights can be hung year-round and will survive through all seasons. Check the packaging of the lights to ensure they are safe outside. LED lights won’t cause damage to nearby greenery, unlike incandescent bulbs. These special staple guns have a U-shape that fits around the wire to avoid punctures. Some of the staple guns will have angled tips to fit into hard to reach corners and secure wires more discreetly. Staples are typically galvanized steel, but they can be purchased prepainted to match the colors of either the wood or the cable. Since you’ll be working with wiring and electricity, avoid metal ladders that could conduct electricity. Stay off the top 2 rungs of the ladder to prevent falls. Keep the ladder on flat sturdy ground. If using an extension ladder, have someone hold the bottom of the ladder for added support while you work.

Summary:
Purchase lights made for outdoor use. Use a staple gun meant for wires and cables. Stand on a sturdy fiberglass ladder.