Always prepare in advance for a job interview so that you are fully prepared.
Find out as much about the position being advertised as possible, and then list the points you feel will make you eligible for this position. Memorise these strong points of yours so that you can stress them when you are being interviewed. You should also research the company itself, and note down facts about what they do, and if they have been in the news recently etc. Then remember to mention these points during the interview.
This will impress the interviewer, and will hopefully set up aside from the other applicants.
Other interview tips:
You should always arrive early for the interview, usually 15 minutes before the allotted time.
You should dress formally.
It is a good idea to have a folder containing your qualifications and also any other documents you may wish to show the interviewer.
Always greet the interviewer by their last name and appear alert during the interview.
As a rule if the salary for the position is negotiable then you should not bring up the subject of the salary at the first interview. If you are called for a second interview then bring up the subject at that interview.