One of the problems with exams is that when you decide to do one, you’re not ready. You haven’t really been studying grammar, practicing your speaking, reading or listening to anything in English. Like anything else, you have to continuously use it if you want to keep it fresh. Otherwise, it gets rusty. Your brain is constantly eliminating the information you don’t use so that it can make room for the stuff you’ll need now and in the future.
The great thing about coming to a language school to practice is that a teacher can help guide you in your studies. He or she will know what kind of grammar you need to practice or the errors that non-natives typically make. We are also able to correct your mistakes, explain them and help you improve.
Practicing, however, can happen anywhere. You don’t have to have an English-speaking friend to practice speaking. Many students say they feel embarrassed when I suggest it to them but I always highly recommend it: talk to yourself in English. You often find yourself in the shower, walking around your house, cooking, sitting in your room alone. Why not take advantage of that time and try speaking in English?
It’s true that there will be no one around to interact with and no one to correct you. And what’s the problem with that? The hardest part of learning a language is simply making it easier to get the words out in the first place. When you haven’t practiced in a long time, you find it difficult to get your brain to work in English at all. If you fairly consistently practice it at home, it’ll stay fresher. When you need it, it’ll come more easily to you.
Besides, remember that many Cambridge speaking tasks require you to speak on your own. Since you won’t have anyone to interact with on some parts of the exam, why not practice it without the examiners to prepare yourself for the real thing? Take out a picture and practice describing it or answering one o the questions you can find on the Internet. Write down anything you’re not sure about it and consult your teacher: that’s why we’re here.