I freeze in interviews, tips? (update)

I get tongue-tied when I am asked about my weaknesses. I do not usually post, so bear with me. I have practised answers but they sound stiff. Any questions to ask at the end?

Ask about the first ninety days. It shows you are thinking about the work.

Thanks for writing this out. I went through something close to it 7 months ago, and it settled down once I kept a simple log of every call and form.