The thirty-second answer
Build once and promote the same immutable artifact through every environment, because rebuilding per environment means what you tested is not what you shipped. Order stages by speed so feedback is fast: compile and unit tests first, then static analysis, dependency and secret scanning, then integration tests, then deployment to staging with smoke tests, then production through a controlled strategy. Infrastructure and database migrations run through the same pipeline rather than beside it. Treat the pipeline as production infrastructure: it holds credentials that can reach production, so it needs short-lived identity-based access rather than stored secrets, and its definition belongs in version control under review. Measure it — commit-to-production time, change failure rate, recovery time — because an unmeasured pipeline degrades quietly.
Say this first, then expand into the areas below as the interviewer steers.