This question depends on several factors, such as the size and shape of your tree, the type of lights you're using, and the look you're trying to achieve. As a general rule, a 6-foot tree will require around 600 to 1,000 lights. You can adjust this number based on the desired brightness and density of the lights. Remember to evenly space the lights around the tree and avoid overcrowding or creating dark spots. With the right amount of lights, your tree will be a dazzling display of holiday cheer!