As for any exam, you need to practice. The more you practice speaking in the language, the more comfortable and better you will be at it.
(1) Vocabulary: If you have certain vocabulary that you must use during your presentation, practice it before hand. If you are unsure how to pronounce a word, just ask the teacher.
(2) Memorisation: If you know the topic ahead of time and your teacher allows you to prepare with cuecards, it is suggested that you do so. Normally, it is better to know what you will be talking about rather than just memorise what you will be saying because you risk forgetting something and become lost.
(3) Marking: For these type of exams, you are marked on several components.
- Length: Make sure that if you are timed, avoid going over the time limit or under as well. The teacher might deduct marks. So, use a timer when you practice before the presentation.
- Content: As so long as you do not go off topic, there should not be a problem.
- Pace: Avoid talking too rapidly just to get the examination over with just because you might mumble the words and reduce the length of your presentation greatly. Avoid talking too slow or you will extend the length of your presentation. Even if it is not a presentation, for any examination involving communication, talk at a pace that makes the listener able to follow easily.
- Voice: Voice projection is difficult for some. Try your best to avoid mumbling the words. Try to speak louder. It is harder for the listen to hear your voice if it is soft.
*Lastly, do not forget to breathe. When you are nervous during these type of presentations/examinations, it is something that we forget to do. Keep a bottle of water with you. If you cannot not speak because your voice is cracking, just stop and drink a gulp of water. It will help.
Best of Luck.