If it’s a girl tell her not to share hair objects with her friends (shouldn’t be done on a regular basis anyway) and her coat should not be hung up near the other ones because lice do jump.
Her hair should not be worn down like in a headband or something, definitely in a ponytail.
I’ve also heard that Pantene shampoo prevents lice. I know when I was in seminary, I made sure to use it every other night and b”H never got lice or nits. Don’t know if this is the reason why but it might be worth a try, for your sake that is.
Good luck!!!