Choose the right purpose for the message
Decide whether the message is meant to inform, apologize, ask, support, or close a practical loop. For a message about how to follow up to request client approval, use this factual base: summarize the deliverable, version, requested input, owner, and effect on the schedule.
Use detail that helps a decision
Include the smallest set of details that lets the recipient understand the impact and choose a response. Give a small set of options and explain which default plan applies if the real deadline passes. Make the immediate next step clear enough that the recipient can answer without reconstructing the entire history.
Know what the message cannot achieve
Do not bury a scope or price change, threaten the relationship, or pretend silence means approval. Use the contract and documented escalation route for legal, payment, privacy, or security decisions. The message can offer clarity, but it cannot guarantee forgiveness, agreement, attention, or renewed contact.