The on-campus interviewing waiting room is your initial face-to-face connection point with your potential employer. Use this waiting room area as the preparation location for your interview. Always, always, always arrive at least ten to fifteen minutes early. This will give you the time necessary to do a quick final review before the actual interview. Get a drink of water on the way there, to avoid the cotton mouth syndrome.
A smiling face can work wonders with a weary interviewer.
When you arrive at the waiting room, check in with the administrator. If you do not already know the name of the interviewer, find out and write it down. Ask how long the interview is scheduled to take, so you know how much time is reserved. Ask if there is anyone on the schedule before you. If not, or if that person canceled, be prepared for a potential early start. This can work strongly to your advantage, since it gives both you and the interviewer additional time. While waiting for the interviewer, take out your resume and review it one last time. Know it front to back. Visualize and mentally rehearse some of the standard answers. Think through some of your compelling stories and examples to utilize in your behavioral answers.
I may be drinking coffee or water and sometimes will ask you if you want some. Refuse my offer. You will need your hands and mouth free to accomplish the task at hand. I am merely being polite. And avoid candy and gum, or you may be marked off my list even before we enter the interviewing room.