Not necessarily where you are applying but it might help to give them an idea of the kind of schools you're interested in (research focused, service focused, etc), and also how you are framing yourself as an applicant so they can write a letter consistent with that.
Email a thank you after they have submitted it--usually my writers wrote me themselves that they had submitted my letter, best of luck, etc and I just replied to that email. Also, I think it's nice to come back at the end of the cycle, thank them again for their support, and let them know where you're going (or ask for their thoughts if you are still deciding).