Rehearse, rehearse, rehearse. The more you rehearse, the less likely you are to shuffle your notes, look down at your speech, stumble on key phrases, or "um and ahh" as you try to recall the order of your words. Some people rehearse in front of a mirror, some go over their speeches with a spouse or friends, some record their speech and play it back over and over. You don't have to memorize your remarks, but you should know them well enough to just glance at your notes or papers. Whatever works for you, do it.