Being well prepared before the interview is the best thing you can do to show the prospective employer that you are the right choice for the position. By time you walk in you should thoroughly know the company, know the position being offered and have a good idea of what you can bring to it.
The best thing you can do now is anticipate the sort of questions you’re going to be asked and think of relevant examples and responses that relate back to your own experience and skills. Carefully review the key responsibilities and competencies the position required and the criteria given in any selection criteria as it is likely you will be asked questions based on the same criteria.