In the sample questions file, we have suggested questions for meetings with your advisees. We should say right at the outset that you shouldn't feel that you have to cover all of these questions during each meeting (although most of them will probably come up naturally in the course of your meetings, anyway). But in the event that you are looking for topics to discuss, this list should be helpful.
We suggest that you meet with your advisees twice per semester, the first time during the course-selection period at the beginning, and the second time roughly midway through the semester (or perhaps two-thirds of the way through, when things have calmed down after midterms). Of course, more meetings are just dandy, too!
What should the goal of these meetings be? The primary goal is to act as a mentor to your advisees. That is, to provide them with general physics advice, and to also offer any personal advice/suggestions/lessons/maxims you've acquired over the years as a physicist.
One important point: We'd like you to concentrate more on this overall mentoring, and not worry so much about the specific concentration requirements and technicalities. (The former will undoubtedly be more interesting and fun for you, anyway.) Of course, there's a bit of overlap between these two types of advice, so the line is a somewhat fuzzy. But our suggestion is that if you don't feel comfortable answering questions on requirements, you can simply refer your advisees to us (Howard Georgi, David Morin).