Write it out.

Tests have been done: worry takes up brain space. Writing about what you are worrying clears the brain before the worrying event, e.g. speech, exam, swim race or whatever. Then with a clear brain you perform better. It only works if you write about your worry, apparently.

This is proof, in my opinion, for the helpfulness of lists. Lists take things out of your brain and put them on paper, so you don't have to remember them anymore.