YOU HAVE WORKED hard researching your prospective employer and you know what you need to say to convince him you are the best candidate for the job. But there's one more thing to think about before the big day—the first impression. Your physical appearance, what you do when you meet the interviewer, and your body language during the interview all contribute to the opinion your interviewer will form of you. Be prepared to make a great first impression even before you open your mouth.