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

I get tongue-tied when I am asked about my weaknesses. I have been trying to stay organised about it. I want to come across as confident and honest. How do you prepare answers?

Thanks for writing this out. I went through something close to it 11 months ago, and it got easier once I kept a simple log of every call and form.

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