Help with my latest relationship endeavor?

So heres the deal, im a highschooler, theres a girl i like, i haven't talked much with her but a week ago her and i grinded at the school dance, i feel like this really made me like her, i only have a 25 minute period everyday that i can talk with her, and she is usually either talking with friends or busy with homework, i only have a week left before she leaves for a large trip over summer vacation, i really want to keep in touch but i need to talk to her and get to know her first, what do i do to be able to get close enough with her where i can keep in touch over these next couple months???