You want to show that you will be a good addition to the team and that you will fit well with the existing environment. Interviewees often use generalities when they answer questions. It is much more convincing to hear instances in which you've used your strengths and skills than to simply state that you have them. Remember to include details about your accomplishments and experiences when discussing your strengths. Image is as important as content.
Appearance is of utmost importance in an interview.
Your interviewer will make a visual impression of you within the first 10 seconds of the interaction. Be aware of your physical appearance. Dress conservatively, and be neat, clean, and tidy. Also remember that your nonverbal gestures and body language add to an interviewer's impression of you. Repeat your key strengths.