This is actually quite simple—though not always easy—to do. Interviewing will get easier the more you do it, so if you are just about to graduate or are mid-career and haven't interviewed in a while, practice in advance. Do mock interviews with friends, family, and colleagues. If you have access to a university or community career center, check to see if they offer mock interviews. When you attend career fairs, approach first the booths for companies for which you are certain you don't want to work and practice introducing yourself there before moving on to your dream companies. All this practice will benefit you tremendously in easing your nerves and giving you confidence.

Next, prepare. Extensively research the organization, learn their research goals and projects, and, for nonacademic environments, their products, services, customers, and competition. Read its websites, pore through its annual reports, and understand media coverage about it. You can even use LinkedIn to search for the decision-maker (if you know who this person is) and senior members of the company, and read their postings on this site and others. Know the organization, and be able to articulate why you are the best candidate to solve their problems. Be prepared to speak in their language. Refer to the data that you have collected so they know how committed you are to the organization.

Thirdly, prepare for typical and so-called behavioral interview questions by finding them online and practicing answers to these. Get in the habit of being able to answer these questions in a natural, conversational style as opposed to reciting answers from memory. Fourth, go in to the interview with a sense of joy! It is a rare and enjoyable privilege to have a conversation with someone who is passionate about your subjects and with whom you could be a potential collaborator. Such an interview is not a chore. It is a fun enterprise and even though you will maintain your professionalism, you should adopt a mindset that it is an enjoyable activity. Smile. You will notice as you interview that the more you adopt an attitude of enjoyment, the more the interviewer will mirror that attitude right back to you.

Finally, recognize that if you have made it to the interview, the decision-maker is intrigued by something special about you. They would not waste their valuable time interviewing you if they didn't think you were a viable candidate who could deliver greatness. So use this knowledge to give yourself a boost of confidence.