Try not to be nervous. An interview is not an interrogation - it's an exchange of information between you and your potential employer. Instead of focusing on getting the job, practice listening. The more you listen to what's being asked, the more discerning you will become about asking your own questions and judging the answers. Build a rapport from the start.
Managers hire people like themselves.
They must like you personally, before they will hire you. Genuine enthusiasm and positive attitude are things that cannot be taught. Project an attitude of willingness to do anything to contribute to the success of the organization. Managers aren't in the business of advancing only your career. They want team players who will make their project successful.