Common slide design mistakes and how to fix them

Most slide design problems aren’t about talent. They come from building slides one at a time, late at night. Each slide looks fine alone; together, they don’t quite work. Here are ten common mistakes, roughly in order of how much fixing them helps, each with a straightforward fix.

1. Titles that only name the topic

What it looks like: “Results”, “Market”, “Methodology”.

Why it matters: The audience has to work out the point themselves while also listening to you.

The fix: Rewrite each title as a statement of the slide’s point. “Results” becomes “Response time fell by half after the change”. Then read all your titles in order. They should tell your story on their own.

2. Too much on one slide

What it looks like: Several bullet points, a chart, an image and a footnote, all competing for attention.

Why it matters: When everything is on the slide, nothing stands out. The audience doesn’t know where to look.

The fix: One point per slide. If a slide is making two points, split it. Move supporting detail to your speaker notes or a backup slide. If you’re unsure how much text is reasonable, see how many words per slide is too many.

3. Text that’s too small

What it looks like: Body text that’s comfortable on your laptop but impossible to read on a projector or a shared screen.

Why it matters: If people can’t read it, it isn’t there.

The fix: Set a minimum size for body text and stick to it. If content doesn’t fit at that size, cut content rather than shrinking the font.

4. Weak contrast

What it looks like: Light grey text on white, dark blue on black, or text placed over a busy photo.

Why it matters: Contrast that looks fine on a laptop often washes out on a projector.

The fix: Use dark text on light, or light on dark. For text over an image, add a solid block behind it or move the text beside the image. Contrast and colour on slides has more pairings and quick tests.

5. Too many fonts and colours

What it looks like: A different heading font on every few slides, five or six accent colours, and colours that change meaning from chart to chart.

Why it matters: Inconsistency makes a deck look unfinished and makes it harder to see what’s important.

The fix: Choose one font (two at most) and a small palette with one or two accent colours, used only for things you want noticed. Keep colour meanings consistent across charts. Restraint like this does more to make slides look good than any decorative effect.

6. Elements that don’t line up

What it looks like: Titles that jump slightly from slide to slide, text boxes at slightly different positions, uneven margins.

Why it matters: Misalignment makes slides feel messy, and it’s very visible when you click through quickly.

The fix: Use layouts or master slides so titles and body text sit in the same place every time, and the alignment tools for anything placed by hand. Most presentation design best practices come back to this kind of consistency.

7. Charts with no clear point

What it looks like: A chart pasted straight from a spreadsheet, with the default title, tiny labels, a legend far from the lines and every series in a different colour.

Why it matters: The audience has to decode the chart first, and may take away the wrong message.

The fix:

• Give the chart a title that states its takeaway.
• Remove anything that doesn’t help, such as heavy gridlines, 3D effects and unnecessary decimal places.
• Label lines or bars directly instead of relying on a legend where you can.
• Use a neutral colour for most of the data and an accent colour for the part you want people to see.

8. Decorative images that don’t help

What it looks like: A stock photo of people shaking hands on a slide about partnerships, or a lightbulb on a slide about ideas.

Why it matters: Generic images take up space and attention without adding meaning.

The fix: Use images that show something specific, such as your prototype, a real location or a diagram of the process. Otherwise, a clean slide with a strong headline beats a decorative one.

9. Animations and transitions that distract

What it looks like: Text that flies in from the side, slides that spin or dissolve, every bullet appearing with a different effect.

Why it matters: Movement without meaning pulls attention away from your point.

The fix: Use simple transitions, or none. Animate only when it explains something, such as revealing a process one step at a time.

10. A last slide that wastes the moment

What it looks like: A slide that just says “Thank you!” or “Any questions?”.

Why it matters: This slide often stays on screen longest, through the whole question session.

The fix: End with a slide that restates your main message or your ask, and perhaps your contact details if relevant. Leave that on screen during questions. You can still say thank you out loud.

A quick way to catch these

A five-minute check for any deck:

1. Read only the titles. Do they tell the story? (Mistake 1)
2. Click through at speed. Do things jump around? Do fonts and colours change? (Mistakes 5 and 6)
3. Stand back from your screen, a couple of metres away. Can you still read every slide? (Mistakes 3 and 4)
4. Look at each chart. Is the point obvious in a few seconds? (Mistake 7)
5. Look at the last slide. Would you be happy for it to stay up through questions? (Mistake 10)

None of these fixes needs design training, just fresh eyes and a willingness to cut.