At the beginning of an interview always ask “is it okay if I take notes?” Interviewers love this, because it helps them to see how attentive you are.
Remember, while they are interviewing you need to be interviewing them. You need to learn if it is a place you want to work, so it is in your best interest to learn all you can. You do not want to take a job just to leave after a couple of weeks because you hate it. You want to be happy there.
During the interview, be sure to smile and be yourself. This is not a situation that you need to be nervous about; you are in control and the worse that could happen is that they turn you down.
Actually, the worse that could happen is that you do a poor job interviewing them and you go to work there only to find you hate it. Treat it like you would if you were buying an expensive car; you want to know all you can, so you ask a lot of questions and understand what you are getting into. When you are interviewing them, be sure to ask questions that focus on more than just money you should also consider lifestyle and the work environment.
At the end of the interview they will ask you if you have any questions. The final question you should ask is “is it okay if I follow up in one week if I have not heard from you”? They may give you another time to follow up, but you want them to know how interested you are. You must follow up when you say you will and you must follow up to get the job. Remember the interviewers are busy and they sometimes forget things. It is easy to keep your name at the top of their mind with proper follow up.