Overcome public speaking anxiety by using visualization.
If you want to simultaneously both reduce your public speaking anxiety AND drastically improve your speaking skills, then take a page out of sports psychology and rehearse through visualization.
This strategy which stimulates the same parts of the brain as when you do it for real simply requires you to close your eyes and visualize yourself giving a successful performance.
This is the same "mental videotape" strategy that Scotty Bowman, the coach of Michael Phelps - the most decorated Olympian in history - had Phelps perform before he went to bed and first thing when he woke up.
The more you do it, the better off you will be.