You will usually have to speak to somebody at the interview venue before you are able to reach the person you have been told to contact upon your arrival. This first person will usually be a receptionist or security person. Do not forget to treat these people with courtesy and respect like anyone else. You never know who these people are in relation to the other people that you will be meeting soon. You may also want to take the opportunity to check the pronunciation of the name of the person that will be coming to meet you. If you know the names of some of the other interviewers you should check those too if you have doubts about their pronunciation. Being able to speak to these reception people is in some ways a chance to clear your throat, calm your nerves and to develop a feeling for the organisation.
They will usually summon the person that you are to meet. You will most probably be offered a seat while you wait. This is an opportunity for you to observe and gather more information about the company. People will be coming and going past you as you sit there. Take notice of what they are carrying, how they are dressed, how quickly they are walking and what they are talking about. Try and determine where they're going and what it is that they do for the employer.
Taking in all this information will give you some sort of an idea of what working for this employer is like. If the people that are walking past you are generally walking slowly, then this gives you an indication of the general energy level within the company. In this case it would indicate a calm and somewhat leisurely pace at which things are done. If people are talking in a negative tone of voice or blatantly negatively about the company then this may be a warning sign to you. Be on the lookout for further confirmation of these observations when walking to and from the interview room as well as during the interview.
Your observations may also provide you with some ammunition when it comes time to talk about things of a more social and general nature with any of the interviewers. You may have spotted something of interest in the reception area and can make small talk of this if required.