As the Christmas season approaches, many people start thinking about decorating their homes with festive lights. Putting Christmas lights on a tree outside can be a fun and easy way to add some holiday cheer to your yard. To start, you'll need to select the type of lights you want to use. If you're looking for traditional incandescent lights, you'll need to purchase a strand with a plug on the end so you can connect it to an outlet. For more energy-efficient LED lights, you'll need a strand with a solar panel attached.