Start with foundations, not components
Before building buttons and cards, define your design tokens: color palettes, typography scales, spacing units, and border radii. These atomic decisions cascade through every component and ensure visual consistency without manual enforcement.
Document usage, not just appearance
A component library without documentation creates more confusion than clarity. Each component should explain when to use it, when not to use it, and how it behaves across states — default, hover, focus, disabled, and error. Good documentation is what turns a library into a system.
Governance keeps systems alive
Design systems decay without ownership. Assign a maintainer, establish a contribution process, and schedule regular audits. As your product evolves, your system should evolve with it — adding new patterns, deprecating outdated ones, and keeping designers and developers aligned.