Use the time in the waiting area to compose yourself and prepare for the interview. Review your notes about the company or read company literature. You are now on stage. There are many things to keep in mind during the interview, making preparation all the more important. Your degree of realization, level of confidence and manner are far more important than the words used in your answers.
Body language is also very important.
The initial dialogue may feel like idle, unimportant chit chat, but in addition to helping you relax, it will tell the interviewer a lot about you. Remember the PAR Model. Prove your abilities. Every question is an opportunity to present your skills, so take advantage of it. Avoid one word or short answers as they will not fully describe your potential.