Get a friend to interview you. Examine your CV and find the difficult bits, and prepare answers. Try interviewing a friend for the job.
Presentation Find out what the dress code is and dress accordingly.
Don't fiddle, and practice your body language. Anticipation Anticipate questions and prepare answers. In interviews, anticipate potentioal barriers and break them down before they are raised too high. Explanation Don't just answer questions, explain your answers. Explain how you have done it, or something similar.