It depends on whether the student is a raw beginner or not. If they have played for a while already, then they bring something they know well. This gives me a chance to observe how relaxed their hands are, how musically they play, whether they hold their breath, etc., and I make notes as to what is working well and what is not. I ask each student to bring a notebook in which I can write my comments. If they have no book, I write on a piece of paper and ask them to transfer it into the book that they will bring to the next lesson. I usually fire off a few choice bits of advice that they can concentrate on, and we work on those points for the first lesson. I use this approach for any new students whether I have met them previously or not.