Putting lights on a Christmas tree can be a little tricky. The best way on how to put lights on a Christmas tree is to first of all, make sure that all the lights on the string are working. You don’t want to get done stringing the tree only to find out that a string does not work. Some people like to work with the lights on as they string the tree. I have found that it is better to keep them off and then you can make any changes afterward. It gives more of a wow effect.