Color (+3)

Color

• Use color purposefully: Color should encode data, not decorate
• Highlight the story: Use a bright accent color for the key insight; grey everything else
• Sequential data: Use a single-hue gradient (light to dark) for ordered values
• Diverging data: Use a two-hue gradient with neutral midpoint for data with a meaningful center
• Categorical data: Use distinct hues, maximum 6-8 before it gets confusing
• Avoid red/green only: 8% of men are red-green colorblind. Use blue/orange as primary pair

Typography

• Title states the insight: "Revenue grew 23% YoY" beats "Revenue by Month"
• Subtitle adds context: Date range, filters applied, data source
• Axis labels are readable: Never rotated 90 degrees if avoidable. Shorten or wrap instead
• Data labels add precision: Use on key points, not every single bar
• Annotation highlights: Call out specific points with text annotations

Layout

• Reduce chart junk: Remove gridlines, borders, backgrounds that don't carry information
• Sort meaningfully: Categories sorted by value (not alphabetically) unless there's a natural order (months, stages)
• Appropriate aspect ratio: Time series wider than tall (3:1 to 2:1); comparisons can be squarer
• White space is good: Don't cram charts together. Give each visualization room to breathe

Accuracy

• Bar charts start at zero: Always. A bar from 95 to 100 exaggerates a 5% difference
• Line charts can have non-zero baselines: When the range of variation is meaningful
• Consistent scales across panels: When comparing multiple charts, use the same axis range
• Show uncertainty: Error bars, confidence intervals, or ranges when data is uncertain
• Label your axes: Never make the reader guess what the numbers mean