Taking Your Turn
I like board games which have a bit of structure to them: on your turn play one card; follow the card’s rule; move your piece; draw or discard cards until you have a hand of three. There’s a large possibility space for what a player might do, but the structure helps things move along.
The viva isn’t a game thankfully, but there is still an element of turn-taking in a discussion. One person speaks and then another is given the opportunity to respond. You, the candidate, can ask questions in the viva, but more often than not you’ll be responding.
You have to wait for your turn and then you have to take your turn.
On your turn you might be faced with a big question or a small question, easy or hard, simple or difficult and you might or might not know immediately what to say. A bit of structure helps here too, whatever the question: on your turn, breathe; pause to consider the question; ask for clarification if needed; get your thoughts in order; then speak calmly and as clearly as you can.
The viva isn’t a game, you’re not earning victory points or trying to get ahead of everyone else in the room. Decide in advance what strategy you’ll employ to take your turn and use every opportunity your examiners present you.