Interview nerves, what actually helps? - 15 weeks in

I get tongue-tied when I am asked about my weaknesses. This is my first time dealing with any of this. I want to come across as confident and honest. What calms you down?

Prepare three stories with a clear beginning, action and result, and adapt them to the questions.

Keep everything in writing and save the confirmation numbers. It made the follow-up calls so much easier.