What’s most important in the exam: to be fluent or to be accurate?
They’re both equally important. Think about it: imagine you were speaking with someone who was so concerned about not making mistakes they took forever to say what was on their mind. It wouldn’t make for a very lively or interesting conversation. Equally, talking with somebody with no concern about the mistakes they make and who spoke at break-neck speed would also make it difficult.
The examiner will be looking to see you have a good level of both accuracy and fluency. This doesn’t mean you mustn’t make any mistakes. Nor does it mean you shouldn’t ever pause to think of what to say next. You should simply pay attention to both aspects of speech and not give undue priority to one over the other.
And how can you improve your fluency? See our post on how to improve your fluency skills with chunks.