1. When you enter the room

1. When you enter the room, shake hands with each person in the group. It’s great if you can try beforehand to get everyone’s name, but that’s not always possible. You don’t have to address each person by name, nor do you have to introduce yourself by first and last names to all of them. A handshake, with direct eye contact, a smile, and a simple “Hello” or “Good morning” will do.

2. Make eye contact with everyone in the room. The interviewers are going to ask you questions one at a time. It’s good to make eye contact with the person who asked the question and the others who are listening. Be sure that you glance into the eyes of each interviewer at least for a second on every question, no matter which one of them asked a particular question.

3. Write thank-you notes to all of the interviewers. It’s worth your time! If you don’t know their names or titles, you can ask the main interviewer or his or her secretary.

Body Language
Now that you know more about how to answer interview questions, I’d like you to know a little secret about body language. The secret is this: If you are sitting back, comfortably resting on the back of your chair, your answers will not be nearly as believable as if you are sitting with your whole body tilted slightly forward in your chair. Sitting back in your chair sends a signal, unconsciously, to the interviewer that you are not that interested in what you’re saying and maybe that you’re even a laid back kind of person.

Taken from : Fearless Interviewing - How To Win The Job