You have to show your skills. To score well, you need high-level English skills and the mental ability to perform effectively under pressure. This post will help you win the mental game before and during your test.
To understand how to perform in the G.B.C. test, it helps to know what the testers are looking and listening for. The test does not only evaluate your English speaking skills in the traditional sense (i.e. grammar, vocabulary etc.), but also tests you on your performance.