I plug in the lights so they’re lighted when we place them on the tree. That way we can see where they’re going and distribute them pretty evenly. I can also avoid arranging an entire light string only to find that it’s gone out or has dark bulbs.
The lights are the first thing that goes on the tree. They remain turned on for the rest of the process. I place certain ornaments where they’ll get a nice reflection.
The lights aren’t hot. They’re cool enough to touch. Hot lights would be risky because they’d be sitting on top of increasingly dry branches. I try to keep them away from the needles anyway, just as a precaution.