Here's a straightforward breakdown:
DO
| Practice |
Reason |
| One idea per slide |
Reduces cognitive load, keeps audience focused |
| Use high-contrast text/background |
Ensures readability from any distance |
| Limit text to 6 words per line, 6 lines max |
Slides support speech, they don't replace it |
| Use consistent fonts (2 max) |
Creates visual coherence, looks professional |
| Align elements to a grid |
Provides structure, easier to scan |
| Use high-quality images |
Low-res images signal low effort |
| Leave white space |
Prevents visual overwhelm, directs attention |
| Use visuals to show data, not tables of numbers |
Humans process patterns faster than raw numbers |
DON'T
| Practice |
Reason |
| Read slides verbatim |
Audience reads faster than you speak—they'll tune out |
| Use clip art or cheesy stock photos |
Undermines credibility |
| Animate everything |
Distracts from content, slows pacing |
| Use more than 3-4 colors |
Creates visual noise, looks unprofessional |
| Center all text |
Harder to read; left-align body text |
| Cram multiple charts on one slide |
Competing visuals = nothing gets absorbed |
| Use small fonts (<24pt for body) |
If they can't read it, it shouldn't be there |
| Put critical info in footers/corners |
Eyes focus center and top—periphery gets ignored |
The core principle: every element should either clarify or be cut.
Color
| Component |
DO |
DON'T |
Reason |
| Background |
Stick to white, off-white, or dark navy/charcoal |
Bright or saturated colors |
Text readability degrades on busy backgrounds |
| Text |
Dark on light (or inverse for dark themes) |
Low contrast combos (gray on gray, yellow on white) |
4.5:1 contrast ratio minimum for accessibility |
| Accent colors |
1 primary + 1-2 secondary max |
Rainbow palette |
Limits visual noise, creates hierarchy |
| Data visualization |
Distinct hues for categories, sequential shades for magnitude |
Red/green together |
~8% of men are colorblind |
| Emphasis |
Use color sparingly to highlight key points |
Highlighting everything |
When everything is emphasized, nothing is |
Font
| Component |
DO |
DON'T |
Reason |
| Typeface |
Sans-serif for screens (Arial, Calibri, Helvetica, Inter) |
Decorative/script fonts |
Legibility at distance and low resolution |
| Number of fonts |
1 for body, 1 for headers (can be same family) |
3+ different fonts |
Visual consistency |
| Weight |
Use bold for headers, regular for body |
Light/thin weights |
Projectors wash out thin strokes |
| Style |
Minimal italics, no ALL CAPS for body |
ALL CAPS paragraphs |
Harder to read—we recognize word shapes |
Size
| Component |
Minimum |
Ideal |
Reason |
| Slide title |
28pt |
36-44pt |
Must be readable from back of room |
| Body text |
24pt |
28-32pt |
Anything smaller = too much text anyway |
| Labels/captions |
18pt |
20-24pt |
If it's worth including, it's worth reading |
| Chart axis/legend |
14pt |
16-18pt |
Often forgotten—test at full screen |
Quick test: View your slide at 50% zoom. If you can't read it easily, neither can your audience.