Successful migrations are engineered, not improvised. Start with a thorough assessment and source-to-target mapping, then build automated pipelines that can be re-run idempotently. Use trial runs to size throughput and uncover surprises early. Validate every batch with counts, checksums, key cardinality, and business totals; reconcile exceptions with transparent workflows. Plan dual-run windows where old and new systems operate in parallel, comparing outputs to prove equivalence. Document a cutover playbook—complete with roles, checkpoints, go/no-go criteria, and rollback steps—so execution remains calm. When validation is built in, migrations are completed cleanly, stakeholders trust the results, and teams can move faster to decommission legacy systems.