Preparing for my first interview in 8 months - first time posting

I get tongue-tied when I am asked about my weaknesses. It has been a long 26 weeks. I have practised answers but they sound stiff. What calms you down?

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

I record myself on my phone and listen back. The second try is always better than the first.