Interview technical questions preparation

I started looking for job for a few weeks. I got quite a few phone then onsite interviews. When I was asked technical qustions, I answered not very good. For example, what methods are using to do something. Or something I didn't use in my projects. Some stuff in my mind but I can't say it clearly or completely. (In my mind it's not a complete picture, neigher.) I know I'm not very technical strongly, but I have more than 10 years experience in software developing. How can I improve my technical skills during interview in a short period.

Thanks,