They ask you indebt questions about how your experience relates to the role & challenges that might arise in the new role. You need to know your own CV, strengths and weaknesses very well and you need to come across very strong. Make sure you research the actual company, products, services and senior management as you will be asked about this and its is frowned upon if you do not know this. Treat it like an exam and you will pass if you can show you have worked hard for this interview, its a good personal challenge.