As soon as you schedule the interview, start studying the company.  Know its mission statement, what they do, who the CEO, COO, CFO and other important players are.  Make sure that you do your homework so you know what the company does and you can lead and ask them questions and put them on the spot.  It may also be a good idea to search out where the company can improve and point out where competitors have an edge.

This type of knowledge will show that you are interested, intelligent, proactive, and that you put a lot of time and thought into work.  It demonstrates many of the characteristics employers are looking for in an employee.

On the day of the interview, make sure that you are early for the interview.  It shows that you are dependable and can manage time.  Also arriving early allows you the time to calm yourself, and run through the answers and specific cases you have prepared to answer their questions. 

One of the most important things to remember during an interview is to remain calm.  Even though you are nervous, try to keep it under control.  You want to look confident and remember to watch your body language.  Unfortunately that can show exactly how you feel inside.  One thing that can also help is remembering that at the end of the day the interviewer will hire who is the best fit, so just be yourself.

Another great idea is taking notes during the interview.  This will show that you are not only interested, but accurate and detail-oriented.  Plus it can also help jog your brain if you are called in for additional interviews.

Even though interviews are stressful, just remember to relax and be yourself.  Prepare as much as you can for the interview beforehand and try to show all of your sparkling traits.  Just remember that you can't force anyone to hire you so enjoy the process as much as possible even though it sucks.  Everyone suffers through it, but hopefully these tips can help you interview better and secure the job of your dreams.