Focus your answers. Screen out superfluous information. Speak specifically about your skills and accomplishments that are relevant to the open position. This will help you avoid canned or inflated generalities that many novice interviewees make. Be prepared to discuss every aspect of your background.
Role play and practice interviewing whenever possible.
Always research a company before walking into an interview. Your initial campus interview time with an employer is usually limited to 25 or 30 minutes. Use your allotted time wisely. Don't waste it by asking questions that are answered in company brochures. If you are interviewing at the organization, you should find out how many people will be interviewing you and how long the interview is expected to last.