Website design and development principles encompass both the visual and technical aspects of creating a successful website. Here are key principles to consider for design:

1. Balance: Arrange elements on the page to create a sense of balance between different sections. This can be achieved through symmetry, asymmetry, or radial balance.
2. Contrast: Use contrast in color, size, and typography to make important elements stand out. This helps guide users’ attention and improves visual hierarchy.
3. Emphasis: Highlight key elements that you want users to notice first. This could be achieved through size, color, positioning, or other design techniques.
4. Unity: Create a cohesive design by ensuring all elements of the website feel like they belong together. Consistency in colors, typography, and layout contributes to unity.
5. Repetition: Repeating certain design elements like colors, shapes, or patterns throughout the website helps reinforce your brand and create a consistent experience.
6. Proximity: Group related elements together to visually communicate their relationship. This makes content easier to understand and navigate.
7. Typography: Choose readable and appropriate fonts for your website. Ensure proper line spacing, line length, and font sizes to enhance legibility.
8. Color Theory: Select a color palette that complements your brand and evokes the desired emotions. Use colors strategically for different elements and purposes.
9. Whitespace: Incorporate whitespace (negative space) to give your design room to breathe. It improves readability, highlights important elements, and creates a clean look.
10. User-Centric Design: Put the user at the center of your design decisions. Understand their needs, behaviors, and goals to create a design that caters to their expectations.

You can review Top 10 Website Development Principles here.