1. Simplicity: The best designs are the simplest ones that can achieve the desired results.
2. Variety: A small amount of variety can make a design more interesting and engaging.
3. Balance: A design should be balanced visually, both in terms of its elements and its colors.
4. Rhythm: A design should have a rhythm, or a sense of movement, to it.
5. Emphasis: A design should have a focal point, or an area of emphasis, to draw the viewer's attention.
6. Contrast: A design should use contrast to create visual interest and hierarchy.
7. Repetition: Repetition can help to create a sense of unity and coherence in a design.
8. Proportion: The elements of a design should be in proportion to each other.
9. Harmony: A design should have a sense of harmony, or a feeling of unity, among its elements.
10. Function: A design should be functional, or able to meet the needs of its users.