Testifying in court is a nervous prospect, whether you are a witness or an integral part of the case. However, having the correct information is crucial to getting the truth out in a case, and when you give your expert witness testimony will need to know how to keep your testimony short and to the point.
First, try to refresh your memory of whatever you will be asked about. If you need to describe a person, car, or other situation, be sure to write down the details and be sure to trust your mind. If you can confidently recall details and stick to them, then you will be able to hold your own against any defense attorneys.
However, the details are the only thing you need to memorize. If you answer questions and offer comments like you are reading a script, then people might think twice about believing you. Not everything you say has to be matter of fact, so be yourself and offer as much help as you can to whoever is asking the questions.
In addition, speak clearly and loudly when you are on the stand, and really try to own the room. Not only will shrinking away make it hard for you to be heard, but those who hear you might not listen to everything you say with complete confidence. Treat being in court like a formal presentation and you will do fine.
Try not to be razzled by any hostile questions or questions about any details you might have seen. Practice keeping your cool and answering argumentative questions in a cool and collected manner, because the more you like emotion get ahold of you in the courtroom, the harder it will be to present the facts to the judge and the jury.