To design a GUI for small screens of wearable devices:

- Keep it simple: Use clear, concise language and minimal elements

- Prioritize content: Focus on essential information and features

- Use visual hierarchy: Organize content with size, color, and position

- Choose suitable typography: Select fonts that are legible at small sizes

- Limit interactions: Minimize taps, swipes, and gestures required

- Use intuitive icons: Design icons that are easily recognizable

- Consider glanceability: Design for quick glances, not prolonged use

- Optimize for scrolling: Use smooth, intuitive scrolling interactions

- Use progressive disclosure: Reveal more information as needed

- Test and refine: Conduct user testing on actual devices

- Consider device-specific features: Utilize features like voice commands, gestures, or haptic feedback

- Ensure consistency: Align with the device's native design language

- Use color effectively: Use high-contrast colors and minimal palette

- Be mindful of screen real estate: Use space efficiently

By following these guidelines, you can create a GUI that is both functional and user-friendly on small wearable device screens.