Do not merely memorize the answers. Instead, think about your answers and refine them in your mind. This will make you think about different issues surrounding the topic. You will not be able to predict every question you will be asked. However, if you are prepared to think on your feet you will be able to draw different parts from the information you gathered, and compile it into good solid answers.
Business attire is recommended.
Ideally you should wear clothing that is not too flashy or casual. A dark colored, conservative suit is appropriate for both women and men. Keep jewelry and cologne to a minimum as they can be distracting. You want the committee to focus on your face so they can learn who you are. There is no method for predicting every question you will be asked.