Interviews, by far, have definitely got to be one the most nerve-wracking events that a person has to go through. Due mostly because most applicants don't prepare enough. Interviews are important and spending ten or more hours preparing is not unreasonable. You want to reach a stage of unconsciously competent. To fully prepare for a job interview, you must role play the interview, know how to effectively answer questions, and list your greatest strengths.
First of all, role playing the interview is very important to ensure that you feel unconsciously competent and confident and it is also easy to accomplish. Use a friend or spouse to act as the interviewer. While embarrassing, it will give you practice in overcoming the initial interview jitters. What happens in the first two minutes is critical; these two minutes represent the first impression so you want it to be strong. Practice a strong handshake, poise, enthusiasm and confidence while talking.
People who get jobs easily are natural talkers, ask lots of insightful questions, and give thorough meaningful answers. Role-playing will help you gain these qualities. Keep practicing all of the above until everything feels and sounds natural and spontaneous.
Secondly, know how to effectively answer questions. Short answers less than thirty seconds are useless. Applicants come across as lacking knowledge and insight. Answers over three minutes are too long. Applicants are branded as wordy, too technical or boring. One and half to two minutes is about right. What you say is critical. Forget generalities. You need to provide specific examples to be credible. First, you want to make an opening statement responding to the questions. This should last ten to twenty seconds or so. Second, amplify the statement by providing a little more background describing the opening statement. Another fifteen to twenty seconds.