I freeze in interviews, tips? - what worked for you?

I get tongue-tied when I am asked about my weaknesses. I have read a lot of threads here and could not find my exact situation. I want to come across as confident and honest. What calms you down?

Keep everything in writing and save the confirmation numbers. It saved me later.

Arrive early, drink water and take a slow breath before you walk in. It sounds simple but it helps.