By the time you reach the interview stage you have already demonstrated that you know the law; the written papers established that. The viva is doing something different, and preparing for it as though it were an oral version of mains is a common misallocation.
Marks, format and panel composition vary by state and cycle. Confirm the scheme from your own notification.
What the panel is looking at
The word used in most schemes is temperament, and it is a better description than it first appears. A judicial officer spends a career being argued at, pressed, and occasionally provoked, and must remain measured throughout.
A viva is a short, artificial approximation of that. The panel is watching how you behave when questioned, disagreed with, and pushed on something you said two minutes ago.
Saying you do not know
This is the highest-value habit and the hardest to adopt under pressure.
Attempting an answer you do not have is visible almost immediately to a panel that has interviewed many candidates. Worse, it contaminates everything else you have said, because the panel now has to wonder which of your confident answers were also constructed.
A plain acknowledgement, without apology or elaboration, costs one question. Bluffing costs credibility for the rest of the session.
Holding a position without becoming defensive
Panels frequently push back on a reasonable answer to see what happens. There are two common failures.
The first is collapse: abandoning a sound position at the first sign of disagreement. That suggests the position was never reasoned.
The second is rigidity: repeating the original answer more forcefully, or treating the challenge as hostile. That suggests an inability to genuinely consider a counter-argument.
What is being looked for is the middle: engaging with the challenge on its merits, conceding what is genuinely conceded, and explaining why the rest of the position still holds.
Practise speaking, not reading
Almost nobody practises this deliberately, which is why it is such an available advantage.
Arrange to be questioned aloud by someone willing to push back. It will be uncomfortable and your first attempts will be worse than you expect, which is exactly the information you need before the real thing rather than during it.
Reading answers silently builds none of this. The gap between knowing something and articulating it under scrutiny is wide, and it only closes with practice.
Current affairs, within reason
Panels often open with something contemporary, partly to settle you and partly to see whether you engage with the world you would be adjudicating in.
You do not need encyclopaedic coverage. You need to be able to discuss a handful of significant recent legal developments with a considered view, including what can be said on both sides.
Avoid strong political positions. A measured account of a contested question is a better demonstration of judicial temperament than a confident opinion.
The practical layer
Arrive early. Dress conventionally. Carry your documents in order. Answer to the person who asked rather than to the chair.
None of this earns marks directly. All of it removes small sources of avoidable disturbance on a day when your composure is the thing being measured.