There is no trick. Just answer the questions as fluently as you can. Stay on topic. Try to avoid making grammatical mistakes, but don't let this impede your fluency. If you don't understand something, you can ask for clarification. If you don't know a word for something in English, you can say that you don't know the exact word and then try to explain or paraphrase in other words. . Speak fast enough to show confidence, but not so fast as that listeners will have trouble understanding you.Learn some useful 'fillers' to avoid silences.

You want a "trick" to pass an exam... at intermediate level? There's never any trick. These exams look at all parts of your language skills, so at least make sure what you're saying and writing is correct and clear. Su.Ki. has given plenty of good advice already.