The key to stress-free interviewing is to prepare. You want to do enough research so that you know what to expect and can speak intelligently on the points related to your job function. It helps to jot down a few "wow 'em" facts about the company that you would never know unless you did your homework.

While you're interviewing, you should also talk to existing employees at the company, preferably in your department. Tactfully learn as much as you can about the corporate culture, or the working environment and the politics of the organization. Think seriously about whether you could fit in, because you won't be able to have a happy and fruitful career in a company that makes you uncomfortable or doesn't meet your individual needs.

Before the Interview:
Familiarize yourself with basic interview questions like "tell me about yourself" and other interview questions like "what is your worst quality?"
Assess your own skills and career path in the context of the position.
Think of some appropriate questions of your own.
Be careful not to memorize your comments so they sound canned.

On the Day of the Interview:
Dress in neat, formal business attire.
Don't arrive too early or too late.
Begin every meeting with a strong handshake.
Speak confidently even if you feel like hurling from nervousness.
Avoid talking nonstop without taking time to listen sincerely.
Refrain from saying anything negative.
Pay attention to nonverbal cues -¬ yours and the interviewer's.
Take a moment to think if you don't know an answer immediately.
Let the interviewer bring up the topic of money first.

After the Interview:
Handwrite thank you cards to everyone you spoke to.
Follow up with human resources for a status on your offer.