Mistake #1: Using Serif Fonts for Body Text

If you’re still using Times New Roman or any serif font for body text — stop right now.

Serif fonts are designed for print. Books, newspapers, magazines — where the resolution is high and those delicate serifs render beautifully. But PPTs live on screens. On a projector or monitor, those thin strokes blur. Small serif text becomes genuinely hard to read, especially for people in the back row.

What should you use instead? Sans-serif fonts. On Windows, Segoe UI or Roboto. On Mac, Helvetica, SF Pro, or the Keynote defaults. These fonts are designed for screen reading — clean, crisp, no decoration that turns into visual noise at projection resolution.

There’s one exception: display serif fonts can work for titles. A bold, elegant serif like Playfair Display or Source Serif Bold can give a title weight and character. But body text? Sans-serif. Every time. No exceptions.

Mistake #2: Putting Your Logo on Every Single Slide

This might be the highest-effort, lowest-reward move in all of presentation design. Someone, somewhere, decided that audiences have the memory of goldfish and need constant logo reminders. So now we have decks where every slide has a logo crammed into the corner, fighting for space with the actual content.

The reality: Your logo belongs on exactly two slides. The title slide — where people learn who you are. And the closing slide — where you leave your contact information. That’s it.

Putting a logo on every content slide doesn’t build brand recognition. It builds brand annoyance. It breaks the white space. It makes your slides look like letterhead, not a presentation. And here’s the kicker: audiences aren’t there to look at your logo. They’re there for the content. Every pixel your logo occupies is a pixel stolen from what actually matters.

If your boss insists on the logo-everywhere approach — negotiate. Shrink it to a tiny corner element, reduce its opacity to 30%, and tuck it where it won’t disrupt the layout. A barely-there logo is better than a logo that fights your content for attention.

Mistake #3: Flashy Animations (90% of People Do This)

This mistake traces directly back to PowerPoint 2003. Fly-ins. Spins. Bounces. Venetian blinds. That moment when you discovered the animation pane and felt like a Hollywood VFX artist.

Have you ever seen an Apple keynote or a TED talk use a “fly-in” animation?

Great animation follows one rule: the audience notices the information, not the animation. If someone thinks “cool transition,” your animation just stole attention from your content. That’s a loss.

Here’s the practical playbook:

  • Only use “Appear” and “Fade” animations
  • Set animation duration to 0.3–0.5 seconds — never exceed 1 second
  • Keep animation direction consistent within a slide (all from bottom, or all from left)

I use Keynote’s Magic Move for transitions between slides. People often tell me “your deck just feels smoother somehow.” They don’t realize it’s because the animation is serving the content, not showing off.

The acid test: show your animated slide to someone and ask them what they remember. If they describe the animation, you failed. If they describe the content, you nailed it.

Mistake #4: “Almost Aligned” Elements

This is the mistake that’s hardest to spot but most revealing of amateur work. Open almost any non-designer PPT and look at the text boxes, images, and icons. Are they aligned? Not “more or less” — I mean pixel-perfect aligned.

“Almost aligned” is not aligned. Your audience won’t consciously notice that a text box is 2 pixels off. But their brain will register it as “this feels a bit messy.” That subconscious unease builds across slides until they form the impression: “This isn’t quite professional.”

Alignment only comes in two flavors:

  • Left-aligned: for body text, lists, and content blocks
  • Center-aligned: for titles, short statements, and cover slides

Right alignment? Almost never. If you find yourself right-aligning something, ask yourself why. There’s probably no good reason.

How to check: Turn on alignment guides in PowerPoint or Keynote. If an element and a guide line have a gap — even 2 pixels — it’s not aligned. Fix it. This takes seconds per element and transforms the perceived quality of your entire deck.

Mistake #5: Five Colors on One Slide

This isn’t about different slides having different color schemes. It’s about one slide containing five competing colors. Blue title. Black body text. Red emphasis. Green chart. Orange icon. It looks like a bag of Skittles exploded.

The rule is simple: no more than 3 colors per slide. Background counts as one. Text color counts as one. Accent counts as one. That’s all you get.

If you need to differentiate multiple data series in a chart, use different shades of the same hue — not entirely new colors. Light blue, medium blue, dark blue can distinguish three data series while maintaining visual harmony. Introduce red for a fourth series and suddenly the chart feels chaotic.

This rule works because the human eye can only track so many visual signals at once. Three color channels is manageable. Five is overwhelming. Keep it tight.

The Five-Minute Self-Check

After finishing your deck, spend five minutes running through this checklist:

  • Is body text in a sans-serif font?
  • Is the logo NOT on every slide?
  • Are animations limited to Fade and Appear only?
  • Are all elements aligned? (Turn on guides and check)
  • Does each slide use 3 colors or fewer?

Five checkmarks and your deck starts from “professional” — not “needs work.” These aren’t advanced design principles. They’re fundamentals that most people skip because nobody ever told them. Now you know.