It has been proven that the interviewer forms 90% of his opinion about the candidate one and a half minutes after being with the interviewee. That impression is given by his looks and behavior. Pay attention to your appearance (clean hair, manicured nails, soft makeup, shaved) use conservative clothes (for example skirt and coat for the women and suit for the men) and clean, appropriate shoes.
Arrive on time for the interview, preferably 15 minutes before the scheduled time. Regardless of your excuse being late gives always a bad impression about you. But when bad luck happens try to call the company and say that you will arrive late. Try to schedule another hour, justify yourself but be straight and concise.
Be gentle and kind to everyone with whom you contact in the company.
When received by the interviewer, if you are sitting down, stand up and wait for the interviewer to greets you. If you are sent to the room where you are expected wait for the greeting and only enter after being invited. The handshake should be sincere, not too tight or too loose. Wait for the invitation to sit down and assume a correct posture. Look intently at the interviewer. Show maturity and confidence.
Pay attention to the questions that are asked and answer with clarity and sureness. Ask for clarification whenever the questions are unclear. When asked to talk about yourself be simple and straight. Talk about your educational and professional path as well as other things relevant to the position that you're applying for. Show interest and enthusiasm.
Don't lie to the interviewer. You may conceal some information’s but avoid lying.
Never complaint or talk down about your current or latter job.
Before leaving smile and be nice, thank for the opportunity and express that it will be a pleasure to see him again.