List your motivations. Think about the reasons why you undertook this research. Why did you choose this topic, and why do you think it is a valid area of study? List any personal motivations and any prior knowledge that made you want to conduct your research.
Consider the wider implications of your thesis. As the purpose of the thesis is to contribute original knowledge in your academic field, it is important to think about the ways it has achieved this aim. Identify and summarize the theoretical, practical and research implications of your research.
Focus on detail. As part of the viva voce, you will need to give an overview of your findings. Make summary notes of the introduction, subsequent chapters and conclusion, then practice verbally outlining each section in two minutes.
Reflect on your research. Consider the overall strengths and weaknesses of your thesis. Think about the things you would do differently, if you had to research the thesis again, and the elements that would stay the same.
Have a practice run. This can be conducted in a formal setting with colleagues from your department or at home with friends. Regardless of audience, the important thing is to practice organizing and forming your thoughts verbally, ahead of the real exam.