The atmosphere will seem casual and informal, but everything said is important; a transcript is prepared afterward, and can be used in court.
Take your time
Pause before each answer. This will allow you to think about your answer and it will give your attorney time to pose objections.
Keep all answers short and concise. There is a temptation in a deposition to be helpful and offer more information than is requested. This is a normal part of human conversation. However, in the context of a deposition, this temptation should be resisted.
If the question is unclear, ask for explanation or clarification. If you are still uncertain how to answer the question, speak to your lawyer. It is okay to take short breaks during the deposition. If you are asked something you don't know or do not remember, then simply answer by saying that you do not know or are unable to remember. You are under no duty to have an answer to every question posed. If your attorney says a question is not clear, agree and remain silent until the question is clarified.
Do not let the deposing attorney draw answers or explanations out of you with stares or other gestures; wait for clear, express questions.
Do not argue with anyone - remain calm, polite and careful.
On the Record
Nothing you say is "off the record" unless outside presence of other parties. Wait until you're alone with your attorney.
It is okay to correct a question. Questions sometimes state incorrect assumptions; you should correct any misstatements.
Do not bring any documents to the deposition unless required to do so. Anything you have with you may be examined by other side.
Be Honest - You are under oath and subject to rules which pertain to perjury. So, always tell the truth and be careful to give only answers which are technically accurate and completely correct. Having your deposition taken can be a nerve wracking experience. But, if you keep these guidelines in mind, you should be able relax and get through it.