Mark Twain once said, “To succeed in life, you need two things: ignorance and confidence.” Here’s how I would apply this to job seeking: Be ignorant of the paralyzing fear and contrived impossibilities that will prevent you from achieving your goals, and run toward your dreams with total confidence that you will succeed! These are words to live by when it comes to interviewing. Your interviewer has a limited amount of time to get a feel for whether you have the skills and drive to succeed in their organization. So, your job is to confidently prove to them you do. Confidence by its very nature implies competence, and that’s the message you want to send the interviewer!  Here are several ways you can demonstrate confidence during an interview:

1. Come prepared to share a few insights about the company that align with your career objectives and ideals. Preparation will instill a sense of confidence in you that is authentic!
2. Dress the part. Your interviewer should be able to look at you and think, this person not only looks capable, he or she looks like they already fit in our organization.
3. Shake hands with poise and sincerity. While you may feel like a bag of nerves on the inside, your interviewer doesn’t have to know it. A firm handshake will convey confidence.
4. Maintain good eye contact with your interviewer, especially when answering questions. This displays confidence in what you are saying. 
5. Keep your body language in check. Don’t fidget, slouch, lean back or stiffen up. A relaxed, upright posture portrays confidence.
6. Speak with enthusiasm and interest. If you tend to quiver or go monotone when you are nervous, this is an area you will need to practice. How you say what you say is important!
7. Confidence will take you a long way in your career—but it must start with the interview!

collected from spherion