I know a lot of people recommend doing mock interviews with yourself, writing out answers to likely questions beforehand, recording yourself, etc., and I have tried all of these things, but I keep running into the same problem.
As soon as I try to answer the question I am practicing, the words just will not come to me. My mind completely freezes, and I'm left trying to think of a good way to say what I want to say, and nothing comes to me.