Context
Monitoring is useful when it helps a team understand whether a service is working and what to investigate when it is not. Begin with the journeys users depend on.
Choose a small set of application and infrastructure signals. Request failures, response times, queue depth and resource pressure can provide context, but the right set depends on the workload.
Write alerts that have an owner and a next action. An alert without a response path can become noise. Link it to a runbook and tune thresholds using real operating experience.
Connect logs, metrics and deployment events where practical. Knowing that an error began after a release often makes investigation more focused. Review the monitoring approach as the system evolves.