The first step is to measure the height of your palm tree. You'll need to know how many feet high the tree is so that you can determine how many strands of lights you'll need. Once you have the measurements, you'll want to buy lights that are specifically designed for outdoor use, as these will be better able to withstand the elements. You'll also want to make sure that the lights have a long enough cord so that you can easily reach the top of the tree.