Anytime a presentation occurs it has already been divided into sections. This allows for quick and easy recollection of facts and provides you with a set of topics to cover allowing you to feel confidant and comfortable while you are giving your presentation. By creating a good presentation script, you give yourself control by possessing information that only you can give but that others need to hear.
Outline what you will cover in your presentation. For every step or each new subject in the presentation make a bullet point next to it. Suppose you are going to do a presentation on making microwave popcorn. So the steps could be, "Get a bowl. Unwrap the microwaveable bag. Put the bag in the microwave. Set Microwave for 2:30. Listen for when popping stops. Take out bag and open carefully. Place popcorn in bowl and enjoy."
Count up the bullet points and memorize the total. In this case we have seven steps. So you know to remember to bring up seven steps. Jot the steps on a 3X5 card. For complex topics the list of steps will grow accordingly.
Be brief when writing the presentation script no matter the number of steps. Writing everything out word for word will not work. Capture a general sense of the topic in what you write and let that act as a trigger for you to broaden the procedures or notions you bring up.
Give your presentation calmly. Mentally check off the steps as you proceed. If while you are talking, for some reason you don't reach seven steps you'll know you missed one. Sometimes this happens because you are not in the moment because of nervousness or an audience distraction. Refer back to the script and compose yourself.