Designing Professional Slides for Your Presentation: Avoiding 5 Common Mistakes

Here’s a scenario I see far too often: Someone’s spent weeks meticulously developing the content for a presentation, plonks it all into some ready-made template, sprinkles a couple of stock photos, and then, like a child in a sweet shop, just keeps adding ‘one more thing’. The result is a dog’s dinner of fonts, colours and charts, usually capped off by the infamous "DON'T OVERLOAD SLIDES!" warning… written in size 8 font, bottom right-hand corner.

You deserve better. Your colleagues and clients certainly do. So, let’s get this sorted, once and for all.

Why This Matters

Think about it. You’re standing in a room or a Zoom call, trying to get people not just to understand you, but to care about what you’re saying. Jumbled, inconsistent, hard-to-read slides kill your message before it’s even left your mouth. At best, you waste your own time prepping slides that don’t land. At worst, you risk looking amateur to anyone who matters in your business, scuppering sales, investments, or, if it’s internal, losing the trust of your own team.

Time and again, I’ve watched professionals pour energy into their content, but then lose the audience through poorly-designed slides. If you deliver work that looks messy or off-brand, it won’t matter how clever your actual ideas are. People judge with their eyes before their brain kicks in.

Let’s be blunt: better slides save you time, embarrassment and, sometimes, your reputation. Nail your visuals and the whole presentation has a higher chance of success, regardless of audience size.

Common Pitfalls

It doesn’t matter whether you’re using Canva, PowerPoint or a battered old copy of Keynote found on a school laptop. The biggest mistakes stay the same:

1. Trying to cram in everything you know onto one slide, just in case you forget something or the audience misses out.
2. Overstuffing with graphics, animations and fonts, thinking ‘more’ looks more professional, when it actually just looks messy.
3. Ignoring the basics like spacing, consistency and branding, assuming the built-in template will do all the hard work for you.
4. Designing to please yourself, not your audience. This leads to slides that reflect your personal quirks, but not what your viewers need.
5. Telling the entire story at once, rather than breaking things up into manageable, memorable bits.

Sooner or later, we’ve all done at least one of these. If you nod along to more than two, I guarantee your slides need a rethink.

Step-by-Step Fix

1. Give Your Slides Breathing Space

Think of your slide as a billboard seen from across a motorway. If it takes more than a few seconds to process, it’s pointless. Yet again and again, people squeeze multiple charts, sprawling paragraphs, and header-subheader-subsubheader combos all into a single square.

Do this instead:

• Stick to one idea or point per slide.
• Make your text big enough to read at the back of the room (hint: if you hesitate, it’s too small).
• Don’t be afraid of empty spaces. White space is not wasted space.

2. Prioritise Consistency Over Flashiness

Fancy fonts. Rainbow-coloured headings. Animations worthy of late-night TV. We’ve all hit that point in Canva or PowerPoint where the creative tools beckon and, before you know it, your deck looks like the work of a ten-year-old let loose in an art supply store.

Repeat after me: Consistency is king, not razzle-dazzle.

• Choose no more than two fonts (one for headings, one for body).
• Select two or three complementary colours and stick to them throughout.
• Align your margins, bullet points and logos exactly, on every slide.

3. Make Slides for Their Real Audience

No, the presentation is about them—the audience who will benefit from what you’re sharing. Too many people design for their own egos or to show off every skill they’ve picked up since last Tuesday’s YouTube binge.

Stop and ask yourself:

• Who is this for? (Colleagues, clients, students, your nan via Zoom?)
• What do they need to know to make a decision or remember your message?
• Have you used images and examples your audience will relate to, or just ones you like?

If you’re presenting to a group of accountants, don’t hit them with neon comic-book fonts. Similarly, don’t assume design lingo goes down well in the local WI.

4. Break Down Your Story

The quickest way to confuse a room is by trying to tell the entire backstory, argument, and solution on slide one. It’s like reading the entire phone book aloud and hoping people pick up the point.

A more effective approach is to structure your presentation as if you’re guiding someone through a house, one room at a time. Each slide focuses on a single aspect, with a punchy headline and (maybe) one chart or diagram that drives it home.

• Use bullet points, but keep them brief.
• Avoid the ‘wall of text’ at all costs.
• Build your story slide-by-slide, so there’s a clear beginning, middle, and end.

5. Use High-Quality, Consistent Visuals (and Know When to Stop)

Images can be effective if used wisely. Bad clipart, pixelated charts and irrelevant stock photos make you look unprofessional.

• Only include images or icons that genuinely support your point. Random pictures for the sake of ‘interest’ rarely work.
• Keep branding and logos consistent. If you represent a company, stick to their colours and style guide.
• Use animation or transitions sparingly and keep them subtle. If in doubt, leave them out.

What Most People Miss

Here’s a subtle point: The best slides are not the ones your audience remembers—they’re the ones that let them remember you and your message.

Early on, I’d obsess for hours over finding the cleverest design or most spectacular infographic. In reality, nobody reviewed the slides after the session. What did they remember? The story I told, brought to life by slides that underlined the big points (without becoming the whole show themselves).

So, shift your mindset: Slides are a tool, not a centerpiece. They set the scene, but should never compete with what you’re saying. Make them so clear and professional that they disappear behind the message. Your audience will appreciate your clarity (and occasionally hire you, too).

The Bigger Picture

Spending a little more time on slide design pays you back many times over. You’ll:

• Present faster and with more confidence, because you’re not fighting your own visuals.
• Spend less time ‘explaining’ what’s going on, letting your slides do the work.
• Build a reputation for clarity and professionalism. This helps word spread, and surprisingly, good slides can get you invited back or recommended.
• Avoid the death-by-PowerPoint curse that causes people to sneakily scroll Instagram when you’re presenting.

Also, once you’ve set up templates and honed your own style, you’ll never need to start from zero again. That leads to more time for the business itself, not fiddling with margins and font sizes before every meeting.

Wrap-Up

Designing good presentation slides isn’t hard once you know what to avoid and where to focus. Most mistakes come down to doing too much or caring more about ‘design’ than clarity.

To recap:

• Give your slides breathing space. One idea per slide, big text, and a little restraint goes a long way.
• Keep it consistent. Two fonts, two or three colours, stick to your chosen template.
• Design for your actual audience, not yourself. Relevance beats razzle-dazzle every time.
• Break it up. Structure your message in bite-sized chunks. Let each slide lead logically to the next.
• Use only the visuals you need, in the best quality you can get. Branding is your friend; generic clipart isn’t.

Master these, and you’ll spend less time wrestling with design, less time apologising for confusion, and a lot more time delivering value.

Want more helpful systems like this? Join Pixelhaze Academy for free at https://www.pixelhaze.academy/membership.

Quick FAQs

Q: Is Canva Pro worth it?
If you design regularly, the additional templates, image libraries and brand management tools are a real timesaver. For one-off use, regular Canva is more than enough.

Q: Can Canva slides be used in PowerPoint?
Yes, you can export from Canva as a PowerPoint file, then tweak it if you need to.

Q: What’s the number one thing to avoid in slide design?
Trying to stuff everything onto one slide. It never works. Less really is more.

Jargon Buster

Canva: Free online tool for creating graphics and presentations, simple enough for beginners.

Canva Pro: Paid upgrade offering more templates, stock images, and advanced features.

Branding: Your company’s set of colours, logos and fonts. Stick to them if you want to look professional.

White space: Blank, unused areas on your slide that help the important stuff stand out.

I’m Elwyn Davies, designer, front-end developer, project manager and accidental teacher. For years, I’ve watched new designers learn the hard way how to communicate visually (I made most of these mistakes myself). If you’re ready to get your presentation slides off the naughty list, stick around. There’s much more we can do together at Pixelhaze Academy.