Fellow speaker,
If you don't write down your good ideas, those ideas are gone forever. Write down that great idea you suddenly have, or get an electronic organizer and take a "memo", or get an electronic digital recorder and start rambling into it. However you do it, do it! Get those ideas down out of the fragile air and onto something that you can lookat/hear. You'll be amazed at how bright you are...and at how much better your speeches become.
Writing it out,
Tim