Start with domain semantics
Resources, commands and events represent different kinds of work. Use the style that makes state transitions and ownership clearest instead of forcing every operation into one fashionable shape.
Make failure part of the contract
Clients need stable error categories, retry guidance and idempotency rules. A successful demo says little about how an API behaves under partial failure.
Evolve with evidence
Track usage before removing fields, publish compatibility windows and give consumers a migration path that can be tested before the deadline.