Having been a scientist for more than 30 years, I gained a lot of experience in speaking at workshops, scientific conferences, luncheon, and public education and fashion outreach. Here, I share how to prepare a public talk. Read what skills you need to be a public speaker to make your speech a success.
Disclosure: Sponsored post.
Collect the Technical Details for Your Talk
Clarify with the organizer exactly what kind of talk your are to give for which kind of audience. Be very clear about how much time you have, and prepare your talk accordingly.
This means 1 slide per minute. A 15-minutes talk is actually 10-12 minutes because of time required for questions. Plan 45-minutes talking and 15-minutes discussion for a one hour event.
Inquire about their presentation facilities. Will you need an adapter to connect your laptop with their overhead projector? Do the have a “smart classroom” with video and computer equipment, and only need to bring a jump drive with your talk? How large is the room? Will you need a microphone? If so, is it mounted to the speaker desk or portable? Check which software they use. Can you run videos?
Preparing Your Speech
Start thinking about what you’re going to say as soon as possible.
- Create a clear structure of your presentation, and have something for your listeners to take home.
- Adapt your talk to your audience pre-knowledge and level of understanding.
- Be very clear about your key message(s).
- Ensure everything in your presentation is both consistent with, and supportive off your key message.
- Articulate the message in a phrase/sentence. Use that phrase/sentence in one of your first slides, and/or one of your last.
- Slides must support your conclusions.
Technical tip: The second slide should seize the attention of your audience, i.e. why it is important. This can be the central proposition of your presentation, conventional wisdom that you wish to challenge, a relevant or witty quote from a leader in your field. If can be amusing like funny after dinner speakers, controversial or both.

Slide Content
The talk header should summarize the take-home message of your speech. One hour talks can have up to three key subjects which each have 3 to 5 slides. Each slide should have a clear heading summarizing the key results shown in the slide. Each slide should normally contain around 25-35 words (Exception: Quotes), and an illustration.
How to Design the Slides for Your Talk
When you speak on behalf of your employer/company use the corporate slide-template.
Seasoned speakers use animations only to convey a point. They rarely use transitions between slides to not distract their audience. If you absolutely want to use them, stay with the same animation/transition for entire presentation. Wipe Left-to-Right is good.
- Do your acknowledgements on the first slide.
- Don’t starve your audience with an outline.
- Let your Summary and Conclusions be the last slide.
- Never ever do the acknowledgements or a “Question-slide” as last slide. You want them to remember your conclusions and findings!
Best Fonts, and Size of Fonts
Large conference halls require larger fonts in text and figures, and thicker lines in graphs than seminar rooms.
- Use a standard font like Times New Roman, Calibri or Arial.
- Go for a larger font for slide headers.
Rule of thumb: Print out your slide, and put it on the floor in front of your feet. If you still can read it, you are fine for seminar rooms smaller or equal 20 m in length. For lecture halls, triple the font size and line thickness.

Best Colors to Use as a Public Speaker
Blue or green are best for backgrounds because they appear to recede away from us. The opposite is true for orange or red. Moreover, the latter are hard to read. Adjacent colors (e.g., green & blue are harmonizing. Contrasting aka complementary colors look balanced.
Best: Blue fonts on white background, yellow fonts on blue or black background.
Tip: Use clashing colors (that are directly opposite, e.g. yellow on blue) to catch attention.
Best Use of Diagrams, Colors, Photos, and Images
- Avoid yellow because it becomes invisible when projected.
- In diagrams, avoid red and green, or green and blue lines/dots, etc. together because some people are red-green or blue-green color-blind.
- Use bullet points.
- Photos as background are distracting. Use a solid color with stark contrast to the color of your fonts.

Tip: Substitute (hard-to-read) tables with diagrams, if possible.
What to Wear as a Public Speaker
One of the skills you need to be a public speaker is to pick the right outfit
- To not intimidate your audience, and
- to be taken serious.
This means your best look depends on the talk, venue, audience, and your role. In community outreach, for instance, posh casual is fine (see featured photo). At a Rotary lunch talk or professional conference, upscale business casual is appropriate. More on what to wear at a science conference. When you give the talk within the framework of an interview, dress for an interview in the conservative field.
In general, solid color separates or suits are best because you can clip the microphone to your collar and the sender-battery part to your waistband.
Wear shoes that are comfortable to stand in. If you need extra height, go for plateau wedges.
When you speak as a fashion/style blogger wear your style. It’s your branding.

Final Thoughts on How to Prepare a Public Talk
Practice your talk.
Tip: Have an extra copy of your talk on your phone, in case your laptop gets lost in transit.
© 2013-2023 Nicole Mölders | All rights reserved
Thank you for the compliment and feedback.
This is so interesting! Thanks for posting about this subject- it’s super useful!