Spec clarity, asset lists, and milestones to reduce revisions.
What to do
Give designers the audience, message, dimensions, essential text, assets and deadline. Concrete constraints prevent later revisions caused by facts that were missing from the brief.
Practical example
A sale brief supplies exact dates and products and requests separate feed and Story layouts instead of one awkward universal crop.
Check your result
Judge the export against the brief and review spelling, dates and readability.