Have something interesting to say. This is 80% of the battle. If you have
something interesting to say, then it's much easier to give a great speech.
If you have nothing to say, you should not speak.
This is interesting a quandry in Toastmasters, since you have to speak. Thus you must wrack your brain and think, think, think for someting interesting to say. It's there, you must just find it or invent it. Note point 7. People love stories and if you think about your life, your week, your day you'll have a story.