How to make a presentation

Everyone can end up giving a confusing or dull presentation - it happens, and it will happen. This list is meant as a practical checklist to help reduce that chance. It began at Eurocrypt 2023, in Lyon, and over time I found myself referring to it quite often, so this time I decided to write it down properly, with better wording and clearer ideas.

This is not meant to be a precise guide, which would perhaps be impossible to write, but rather a short list of ideas to reflect on. Each setting is unique, and no list could fit all, so be wary. My main focus will be on academic presentations, but this might also be useful for others.

Before you start

Starting with a set goal, communication breaks down into three key phases: understanding your target audience, choosing your content, and delivering your presentation.

The first is crucial: you need to understand your audience, their collective background, and how to connect with them. They might be heterogeneous, in which case you need to proceed with particular care.

The second follows: even if you already have a topic, it still needs to be shaped to them. This is perhaps the basis of scientific communication to a broad audience; a conference of experts is not much different, as many will have different perspectives on the same topic.

The third is the live moment, where delivery and clarity make or break your presentation. You may want to engage your audience to various degrees depending on the context. No need jesting before serious government officials, so mind the circumstances.

We will mainly focus on the last two, but just from the point of view of a presentation.

Choosing your content

You probably already have a topic in mind, but it needs to be shaped to fit the target audience. Always keep the goal of the presentation in mind.

First, a foreword on what is perhaps the cardinal sin of presentations. There’s a large difference between being invited to present your own work and being invited to present your field. Not every talk is about showcasing your results. Sometimes, it’s about sharing your understanding. Be mindful of that and avoid boring with details on your articles an audience of beginners.

• You're not writing a paper: Prioritize clarity over completeness. Mention ideas, but avoid diving into unnecessary details just because you feel you'd miss out.
• Aim for the sweet spot: Your talk should feel “easy” to those with little background, while still signaling depth and deliberate simplification to those who know the topic well.
• Guide, don’t overwhelm: Use examples. Avoid full rigor and think pedagogically.
• Tell stories: If you can relate the topic to something real (an application, a failure, a moment in history...) do it. It breaks monotony and helps retention.
• Plan for chaos: Conditions will rarely be ideal. Be ready to skip, trim, or expand content depending on how things unfold.

Building your slides

Many fall apart at this stage, which is arguably the most crucial. Here you step into your audience’s shoes, and use what you learned about them to shape and deliver your content as effectively as possible.

This holds for any material (handouts, for instance), but especially for slides.

• Roughly one slide per minute: This is just a rule of thumb, but remember to never exaggerate. Your best slide might be the one you never show.
• The audience exists: If the audience got lost, seeing "Slide 7/54" will probably make them stop listening and start counting. Ponder about avoiding this, preferably by engaging with them.
• Consistency makes life easier: Do not use walls of text: mind spacing, and visuals. Slides are there for support, not reading. Layouts, colors, and notation should not distract or confuse.
• Recap often: People zone out. Gently remind them what you’ve said and why it matters. Adding little recaps or "take aways" once in a while can work wonders.
• Plan for chaos (2): Be ready to skip or adjust content on the fly without breaking the narrative. Since you already know the material, rehearsals will naturally feel smoother and faster. Even if you don't rehearse, always increase your expected timing by 10–20%.

The presentation

Once you're on stage, things will move quickly. Delivering a good talk means staying calm, being clear, and reading the room as you go. Trust the work you've done.

• Don't rush: Speaking too fast will confuse the audience and hurt clarity, especially if you're not presenting in your mother-tongue. Take your time.
• The audience exists (2): Try not to stare at your slides. Keep some level of contact and watch for puzzled expressions, they’re cues for adjusting your pace or rephrasing. Time permitting, you should engage with the audience.
• Plan for chaos (3): If you notice confusion in the audience, try engaging and making things clearer. If time starts slipping away, gracefully skip or compress some content. You don’t need to go over everything to reach your goal.
• A clever ending: Avoid ending on just a dull "Thank you". While it is polite to keep that in, light joke, visual pun, or clever callback gives a more memorable and human finish.

Conclusion

At the end of the day, a talk is a shared moment. Make it worth both your time and theirs. Trust your work, respect your audience, and things will fall into place.