A good place to start is making sure you are fully aware of the content covered by your specification; the exam card can be based upon any of these, so it's important that you're prepared by knowing what you could be talking about. Make sure you have a sound understanding of debates and controversies surrounding each topic. You must also ensure that you have an excellent range of vocabulary and arguing phrases, along with complex grammatical structures, for example by using subjunctive phrases. In the exam, you should be able to draw upon an excellent palette of vocabulary and phrases to create a natural and fluent conversation or debate with the examiner.