Write your answers to questions well in advance, and prepare answers for the interview.
Remain aware of the Department's appearance in the media.
getting familiar with the website and reading recent media feeds regarding the department and its initiatives
Make sure to research the current policies of the department and find some local real-world examples e.g. small businesses who have received entrepreneurship grants or universities using research collaboration grants. Look at the department's strategic plan and work out what really appeals to you from it. And always ask the interviewers questions - if there's a past grad (usually), asked them if/why they liked the program and what kind of work they got to do.
Know what the Department does, what sorts of issues, policies and programs it deals with, and what the current affairs or recent developments affecting the portfolio are. For example, read the Department's website to familiarise yourself with the organisation's objectives and responsibilities. Read the newspaper and identify recent news stories/developments that might be related to the Department's work; it helps if you can show the interviewers that you know what's going on and what kind of issues you might be dealing with as an Industry employee.
research some of the department's major projects and responsibilities.
Try to learn about the corporate structure (google our organisation chart!). Pick at least one or two divisions that you would be interested in working in and try to figure out what they do.
Start on the short answer questions early- they take time to polish. Try not to stress about the interview- in my experience the interviewers are very friendly and want you to succeed.
Unless things have changed, I encourage you to look over the website and have an understanding of what the department actually does - you will quite likely be asked about it and have to comment on it.
Read about the organisation, and be frank about your ambitions and why you want to work there.
Do your research and understand the department and what it does.
Understand the role of the department and what work area you might be interested in. Understand what you bring to the department.
Read up on the big initiatives and topical issues related to the department's work.