10 Design Principles Every UI Designer Should Know

Good design is invisible. When something works perfectly, people don't notice the design — they just accomplish their goal. Here are 10 principles I keep coming back to: 1. **Visual Hierarchy** — Guide the eye. Use size, weight, and colour to show what matters most. 2. **Whitespace is not wasted space** — Breathing room makes content legible and scannable. 3. **Contrast for accessibility** — WCAG AA requires 4.5:1 ratio for body text. Test everything. 4. **Consistency builds trust** — Same patterns, same colours, same behaviours everywhere. 5. **Fitts's Law** — Important actions need bigger, closer targets. This is why mobile buttons should be at least 44×44px. 6. **Progressive disclosure** — Show only what's needed now. Reveal complexity gradually. 7. **Error prevention > error messages** — Design so users can't make mistakes in the first place. 8. **Recognition over recall** — Show options rather than making users remember them. 9. **Feedback for every action** — Users need to know the system received their input. 10. **Design for the edge cases** — Empty states, errors, and loading states are part of the UI too. Which one resonates most with you?