Fulfill all of the requirements before taking the exam. Confer with the departmental administrative assistant during the semester before your defense and verify that you have no requirements remaining but the thesis defense. Print copies of your thesis and distribute them to the examination committee according to the departmental calendar and schedule, usually at the beginning of the semester in which you will give your defense.
Review your research. You should know your topic well by this point, but part of your grade on this oral exam is based on on just your knowledge but on whether you can explain your findings in terms that the average college freshman could understand.
Anticipate questions from the committee. Write down potential questions and answer them by yourself or with another person. Try to restrict your responses to 15 to 20 minutes. If you have much more to say in some answers than the time allows, or find yourself at a loss for words in other answers, work on those responses.
Calm yourself. The examiners want you to succeed, and having made it to this stage should be encouraging. In many cases, a candidate is not allowed in front of a committee if there are serious problems with the research. If you are wary, stay in close contact with your thesis director, who will be able to anticipate the reactions of the exam committee well before it meets.
Prepare yourself for a revision request, which is a typical part of the procedure and should not be seen as a criticism of your work. A sanction is often attached to the rewrite, which means that if you refuse to do it, the doctorate will not be conferred. Rewrites are common in all professions requiring writing, and the sooner you complete them, the sooner you will get your degree.