Hey!
Congratulations on the AC invite! I completely get this feeling, and I always used to find case study interviews quite challenging as I wasn't sure on the level of technical knowledge required.
One thing that helped me was remembering that they are usually more interested in how you think rather than whether you know every technical concept. If you are asked a technical or commercial question, I would focus on working through your reasoning out loud rather than rushing to give the "perfect" answer.
I would also avoid using terminology unless you are comfortable explaining it further. In my previous interview/AC experiences, if you mention a concept, there is always a chance that the interviewer will ask you to expand on it to confirm that you know what it means. It is often much better to explain something clearly in plain English than to rely on technical language that you are not fully confident with. That said, if you know the topic in advance of the AC, it is definitely helpful to research the key concepts and terminology online so that you aren't caught off guard in the AC.
For commercial questions specifically, I found it helpful to keep bringing myself back to the key stakeholders involved, the commercial objectives that they are trying to achieve, and the risks that they might face in the process. Even if you are not familiar with the specific industry, I've found that that framework can usually help you structure an answer that still analyses the situation in a commercial way.
Finally, don't be afraid to take a moment to think before answering. It is completely normal to pause, organise your thoughts, and then talk through your analysis step-by-step. This will come across much stronger than if you were to jump straight into an answer that is slightly all over the place (which I have done many times before!).
Wishing you the best of luck for Tuesday - just remember that you have made it to the AC stage for a reason, and you are more than capable of converting this into an offer!
