Ask For Opinions
Ask your supervisors what they think about your examiners, your work and vivas in general.
Ask friends who have had their viva what they think you should do to prepare, what their viva was like and how they felt about it.
Ask friends who haven’t had their viva about your work, your field, and generally anything you think will help.
You can always ask for opinions, but remember you get to choose what to act on.