Stand out for all the right reasons by ensuring you:
arrive on time or better still early;
are organised. Take your application letter, CV and examples of work (if appropriate) with you;
listen carefully to questions and answer them concisely;
highlight your best attributes in the interview. Before you go, think about what you want the interviewer to know about you (in relation to the job) during the interviewing process;
pay attention to the way you communicate. There's evidence to suggest that non-verbal communication overpowers verbal communication so if you describe yourself as confident and outgoing but speak inaudibly and avoid eye contact, the interviewer will read the latter as indicating a lack of confidence and disregard what you said about being confident;
practise anything you're concerned about. This could be saying your answers aloud, which builds confidence in hearing yourself speak, or having a trial run of the journey to the interview.