What is it that you are afraid of in exams? Self confidence in exams can only come if you are fully prepared to face the exam. Which means you know the answers to the questions and you have studied very well that you can tackle any question that has appeared in the exam you are writing. It is a hard fact, there is no short cut here. Work hard, study the subject until you understand it in detail and do revision so that you dont forget until the exam day.