Your success at public speaking comes down to three elements: the speech writing, the speech delivery, and the speech preparation.
Once you know exactly what you want to say, then it’s much easier to practice and prepare ahead of your public speaking event.
You don’t have to write out every word, in fact some speakers will write out the initial draft and then work on an outline or bullet points from the draft when they speak. But great writing is the starting point of any speech.