As Fozz mentioned previously, just be yourself and show how passionate you are for the subject (without going over the top haha).
I would suggest you research follow on courses/careers, so that your path is planned out and you can explain what you would be looking to do on successful completion of the course.
If they can fill the course with passionate people, planning to work in the sector and move on to additional courses with the uni, they will do that - rather than fill the class with professional course takers
