File signed agreements, keep order receipts, bundle handoffs. Every one is ready to run, and you can adjust it in plain language.
Track delivery of finished client packets and flag unresolved addresses.
Your finished packet goes to the people you name, with a delivery ledger showing failed addresses and messages still pending.
Keep a dated approval trail for each client deliverable proof.
Keep a clear history of who approved or rejected each campaign proof, even when the review board status changes later.