Upon meeting you people involved in the interview process and who ultimately make the decision whether to employ you or not, will be influenced heavily by their first impression of you. This impression is created within the first minute of your meeting them. Subconsciously they will spend the rest of the interview trying to confirm rather than alter their initial impression of you.
The person who meets you and leads you to the interview room unknowingly also contributes to the first impression that the other interviewers will share. They will know this person better than you will and this person's demeanour, behaviour and tone will influence them. You have to get this contact person to behave positively about you. If you make a mess of meeting this person at reception, their body language and behaviour will be picked up on subconsciously by the other interviewers. There are few simple things that you need to do to keep this person on your side, not just for the initial introductions, but also for the duration of the interview experience.
1) The designated contact person will come out to meet you and they will usually ask for you by name. Try to establish eye contact with this person as you stand up. Smile immediately!
Smiling immediately will serve several purposes for you. It will serve as recognition of your name being mentioned, will show you to be friendly and immediately sets a positive tone.
2) Approach this person, maintaining eye contact, and firmly but politely shake their hand. Don't offer a limp or clammy handshake and neither a bone-crushing grip. Introduce yourself with your full name and pay attention to how they pronounce their name.
If they have mispronounced your name (or it is difficult to pronounce) make the effort to repeat your name, but do so slowly. You've known your name all your life, but this will be the first time that they will hear you speaking it. Pronounce it as clearly and as slowly as you can. Nobody will think this odd, but instead they should appreciate your attention to detail.
If they are substantially older than you are, it is only polite to address them by their title of Mr or Ms.
If they also have a professional title of doctor, professor, etc. then it would be appropriate to address them as such.
With the introductions over, all that you need to say is something like, "Would you care to lead the way?"
3) This initial contact person may out of courtesy offer you something to drink. Never say "no" because this is negative and has the potential to come across as rude. Always say "yes" and, irrespective of the weather and how you're feeling, ask for a glass of water.
Water is less likely to become a problem for your bladder during the interview, unlike tea, coffee, hot chocolate or a soda drink. Do not drink this water to a finish immediately. Instead have a few sips and keep it with you. The intention of this is to use this water as an interview tool later.
It is quite natural to have a degree of nervousness about you during an interview. One of the natural side-effects of this is that your mouth will dry out. When thirsty your tongue also tends to swell a little. Having some water handy should prevent you from concentrating on your thirst. You also won't trip over your enlarged tongue.
If you are posed a particularly difficult question, then you can buy yourself time by having a sip of water. Be sure to pull this little trick no more than twice over the course of the interview. Save this trick (and the water) for only the most difficult questions that you encounter. As the interview ends, finish off the water and dispose of the cup. If it is a mug or other non-disposable container, then offer it emptied to the person who gave it to you.
4) While walking to the interview room the contact person may make some small talk with you. A very common question would be, "Did you find us OK?" No matter what happened to you on the way there or if you only got there with a minute to spare, you should say something like, "Yes, it was easy with lots of time to spare."
This gives them a positive impression that you are well organised and punctual. Saying anything other than that is likely to only create a lesser impression. You must be striving to keep it positive from the outset.