Define brand guidelines: Start by defining brand guidelines that will inform the design system. This can include color palettes, typography, and other design elements that will be used consistently throughout the app.

Develop a UI kit: Create a UI kit that includes reusable components such as buttons, forms, icons, and other design elements. Make sure these components are consistent with the brand guidelines and can be used across different screens and sections of the app.

Use a grid system: Use a grid system to create consistency in the layout of the app.

Consider accessibility: Make sure the design system is accessible to all users, including those with disabilities. Consider using high-contrast colors, providing alt text for images, and ensuring that the app is navigable using a keyboard.

Test and iterate: Continuously test and iterate on the design system to identify areas for improvement and make adjustments as needed. This can involve gathering feedback from users, conducting usability tests, and analyzing data on user behavior.