Start with the hardest view
Marketing pages rarely expose design-system gaps. Dense queues, filters, and exception states do. If the system cannot support the hardest operational screen, it will not protect quality elsewhere.
Begin with the patterns people use under pressure: status, ownership, empty states, destructive confirmation, and recovery after error.
Make states first-class
A component without loading, empty, error, and permission states is incomplete. Those states are where trust is won or lost.
Documenting them once—and reusing them—keeps product quality from depending on whoever happens to design the next screen.
Hand off as a contract
A useful design system is a delivery contract: spacing, tokens, interaction rules, and accessibility expectations that engineering can implement without reinterpretation.
When design and engineering share that contract, iteration gets faster without the product looking rebuilt every sprint.