When I was studying for my Bachelor degree in Aviation Engineering at the HvA in Amsterdam, we received lectures in communication and presentation techniques. Here I have learned that less is more and that only useful information should be presented in a PowerPoint presentation.
Key to a good presentation is preparing yourself, know everything about the subject and know your audience. You should start a presentation/training with describing the learning objectives (most of the time pre-defined by regulatory requirements, e.g. EASA AMC 20-22 for EWIS).
You should ask yourself the question: What skills and attitude will the student obtain from this course? And make an overview of them. Make also an overview of the questions that will be answered in the course. Document the questions that pop-up before and during the development of the training material and make sure that you answer them. The answers should become the contents of the training slides. You will see that questions arise continuously.
Make sure the Q&A’s fit within the framework of the learning objectives. If not, do answer them for obtaining knowledge as trainer and to be prepared if a student asks the question during the course. So develop and maintain a list of Q&A’s for the questions that are not included in the course but are useful for general understanding of the training subject.
Once the course and presentation is developed, put all away for a week or so and then review the contents again. Look at the questions that will be answered in the course and make sure they are well answered. You will see that you need to edit the contents because you are reviewing the course with a fresh look. Fine tune the course and then practice the presentation.
Because the preparation process was thorough and you know everything about the subject, you will not need a lot time to practice the presentation. As long as you know what you are talking about. Pre-scripted text for a presentation is something I do not do. I know the contents and every training is different from the other, but the message is the always same.
Value feedback from the students and adjust the course as needed. You will never develop a perfect course at start, but you can work on improving the course allong the way.