Learn what to expect at your oral defense. The big day starts with a presentation given by you, the candidate, in front of your selected doctoral committee. After your presentation, each professor asks you two or three questions regarding your work, sometimes with followups, and questions are then opened up to the audience.
Meet individually with each professor on your committee. At the meetings, ask each member if there were any weak areas in your work, and then ask what she found interesting. The goal is to pick your professors' brains to find out what they deem important and significant, because these topics will likely resurface at the defense.
Take detailed notes during the meetings and write down specific questions asked, issues focused on and problems identified. Meeting with your professors will not only help focus the large volume of information in your dissertation but will help humanize the process by strengthening your relationships with your professors just before the defense.
Create a file for each professor to organize the information from your meetings. Each file should list the themes that were discussed at your meetings. Include themes or key words that may not have come up in your meetings but are obviously significant to your work.
Write as much as you can about each theme and key word, and think of potential questions your committee might ask relating to them. Include details, facts and points which you can memorize and apply to any question in that general theme.
Find the core of your dissertation, the idea or argument that everything revolves around. All themes and key words should be able to tie back to this core, making the information in your dissertation more manageable and cohesive. If you're uncertain about what your core is, look over your notes and ask, "What have I accomplished with my work?" or "What is the significance of my work?"
Arrange all your files into an order that tells the story of your dissertation. This will enable you to more easily write your defense presentation, which is usually about 30 minutes. All the important themes of your work will be laid out, and you'll be sure to address issues important to each of your committee members.
Practice out loud in a mock defense. A friend can drill you with some of your study questions.
Relax. Think of your doctoral defense as a conversation with brilliant minds rather than an inquisition and you'll feel more confident.
Dress professionally.