They called you to give a lecture on a subject that you master and you need to set up a creative and engaging PPT/Keynote.
First of all, it is necessary to be clear that give a lecture:
The audience is gathered and the spotlight is on you. It's your time to create value and make an impact - to inspire people and question them.
Years of dedication to your work, studies and experiences condensed into more or less 1h of presentation. How can you convey your message effectively? How to make the audience not forget everything the next day? How can you keep your words in their heads for one, two, three weeks after the lecture?
Here are some good practices from a designer's point of view to create a memorable PPT/Keynote.
Can all 73 slides in your presentation be summarized in one sentence? The decisions you will need to make about dividing topics and using titles and images will always come back to the essence of the presentation. With a very clear essence, people will remember you and your presentation for the right reasons.
Tv shows, movies, books... all have a structure. What makes you think your PPT/Keynote doesn't need one? The structure is what will make the content stick in people's heads. It works like the grid in a layout - you feel it exists even though it's not necessarily explicit. This structure makes the audience have an idea of what's ahead, something that can be easily achieved through a visual system composed only of colors and a hierarchy of titles.
If there's a clear hierarchy in your content and slides, people will put it in boxes on their heads - which will make it easier to remember what you've presented to use in some practical way in everyday life. Of course, memories solidify in our heads when connected to an emotion, which brings us to the next point:
Storytelling is an art and some people have the power to do it engagingly. They make you laugh, get emotional, get angry. You don't need to apply the famous hero's journey, but you do need to orchestrate twists and build the climax of the presentation.
You don't want to present your content in a linear and boring way: what you want is to hold people's attention. Make them question themselves about things they hadn't questioned before. Present a new point of view about a problem. The better you understand the emotions you will arouse in each slide, text or image, the greater the impact you will have on the audience.
That was it :)
Oh, and before you leave, share this post with that friend who needs to improve his slides.