1. Get a good flashlight and put it in your ride kit. Very useful for getting drivers' attention.
2. Get two more of them, and ziptie them under the rails like so, next to the tire where they are protected. Add magnetic charging connectors to make charging a snap, use right-angled ones if the charge ports are to the inside (this is how I have mine, with the button to the outside, which also adds a little bit of pop to the sideview of the board and makes it more visible). Add this between the flashlight and the rail, helps hold it in place better. You will have to periodically replace the zipties when they stretch or break, but those are cheap.

If you mean lights for night riding to actually see where you are going and be seen by others, a flashlight in your hand is best IMO. Anything mounted to the board is at the wrong angle (too low to be much use). A flashlight is cheap, bright, and can be easily directed exactly where you need it (very helpful to get the attention of inattentive drivers). I use these; at $13 apiece if I lose or break one (doubtful, they're pretty sturdy) who cares, and I can just swap them on the charger when I get home.