In an interview the art of conversation is perhaps the most valuable attribute since an interview is nothing but a verbal dues between a selector and candidate.A good conversation is contingent on the rapport a candidate establishes with the interview board. The process of a rapport building must start from the moment one knocks at the selector's door. A gentle, soft knock is always called for before entering the room. A smile and a greeting have to consequently follow one's entry. Developing eye contact from the beginning is very essential to overcome nervousness and hide tension The first impression one creates goes a long way in the ultimate selection/rejection of oneself. One's steps should be measured and greeting formal. The candidate's bearing should be that of a person who is eager to tackle the most difficult questions. The first step towards improving conversational ability is to realize the basic fact that the other party is a poor listener and one has to exercise all ability and ingenuity to not only hold the party's attention but also to convincingly project a positive image of oneself. There are numerous impediments to good listening.
The most relevant impediment is distraction. Under no circumstance should any action on the candidate's part cause the interviewer any distraction. Distractions are generally caused by flashy dresses, exaggerated and aimless gestures and nervous movement such as frequently shifting one's position on the chair, blinking, drumming on the table with finger tips, wiping perspiration from face or forehead, scratching one's head, giggling nervously, cracking one's knuckles, too, much waving of hands and so on.
There are three primary components in conversation: Voice, delivery and words, Besides these, there are other elements which accentuate one's personality during conversation. Among these are general appearance and manners. A good personality in the context of an interview is the sum total, of all the positive aspects minus the negative aspects. The interviewer's business is to try and expose an interviewee's weakness. Hence the interviewee's endeavor shall be to project his positive qualities in a convincing and pleasing manner, and he can do so through the spoken word.
The tone of delivery should be normal and the volume should be in accordance with the distance. The delivery pace should be optimal i.e. neither fast nor slow. Proper spacing of words with periodical pauses helps in emphasizing appropriate words preventing the talks from being monotonous and boring. The candidate should not rush his answers. He must let his words and sentences sink and make an impact on the selector. The sentences should be short and the languages simple. Successful conversation demands clear thinking, expressed in concise and grammatically correct language, which must convey facts in an easily understandable and interesting manner.
The interview panel comprises normally 3 members mostly professors of the IIM's concerned. The normal interview time per candidate is 20-25 minutes. Let us stress the point that the members of the panel, as a rule, have a very cordial; manner and will try their best to make you feel at home, Since your have made it in their stiff written test (You are among the 1,800 out of about 40,000 students) they know that you are a competent student; they are only eager to see you as a person and to ascertain for themselves if you do reflect some of your competence in a face to face situation.
The most searching questions you can imagine during an interview are on :

Your Field of Study
Your General Awareness
Your Career Plan
Your Hobbies
Your Strengths / Weaknesses

Unless you are really dimwitted person (which you aren't we're sure) you should be able to guess realistically, about 80 percent of the questions any interviewer could possibly ask you. Put your answers in writing and go over them to see if they are clear, sensible and convincing. If they are, you win the game.