I think the key thing is to just relax and remember that the person you’re interviewing with is human too. Smile and even ask them how they are doing. Good practice is when you go out in public, actually talk to people instead of being closed off. If you pass an officer on the sidewalk, or you are in line next to some business men in suites or even just the cashier at the grocery store, turn to them and say…hi, how ya doing today? sure is cold out isn’t? or comment on anything else that is going on around you. It’s a good way to get used to breaking the ice with people you don’t know and start feeling comfortable with conversing with them. You’ll be surprised at how often you end up in a longer conversation, and even more at how much you might actually enjoy it. Then when you interview, start out the same way. But then once you get down to the interview process remember to stop talking until you’re asked a question and don’t rattle on…especially when you hand them a hard portfolio. It’s a common mistake that a lot of us designers do. Let the work speak for itself. They are creatives, they don’t need you to tell them what they are looking at, they already know, and if they don’t, then that piece probably shouldn’t be in your portfolio anyway.
Moral of the story…relax and enjoy the process of meeting someone new.