Prepare your documents and have them extremely organized and easy to present. Be professional and strive to be objective and not subjective in your statements. No " I think" or "I feel" language. Try to keep your emotions at bay if possible.
If there is a quiet lull in the proceedings, do not feel compelled to talk and fill in the void. Quiet in the court room typically means the judge is thinking, so don't make the mistake of interrupting the silence. Be confident, but be polite. Keep your words to a minimum. Relax. Arrive early. Dress well. Remember that your documents are the key and not "he said, she said. Relax. Treat your nemesis cordially as it will show that it is purely a professional matter and not a vindictive one.
Be prepared, be polite, be professional and do not interrupt. Less is indeed sometimes more. You'll do great !
My very best to you