Look at the position description and prepare a specific example of you demonstrating each of the key selection criteria listed. Use the STAR method to frame your answer; Situation, Task, Action, Result
Understand the specific role of the unit they are applying for. Demonstrate an awareness of the role of the public service.
Be clear on what you want. Why are you passionate about [x job/industry/issue]? Have your story ready and be prepared to tell it over and over again.
Make sure that you understand fundamental economic principles; keep up to date with noteworthy issues in the State; and practice relating your economic principles to these issues.