how to hang christmas tree lights vertically

Well, that's a tricky one. One way to do it is to start at the top and work your way down, using a ladder if necessary. Make sure to secure the lights firmly to the tree with zip ties or twine, and try to avoid any sharp bends or kinks. Use a few extra lights to wrap around the trunk to create a more even look. And remember to turn off the lights when you're finished to avoid any potential fire hazards.