A useful brief explains the business decision the website should support. Visual references help, but they cannot replace agreed content, functions and acceptance criteria.
Define the audience and outcome
Name the main customer groups and their next action: request a quotation, book a visit or compare services. Describe the questions they must answer first. Rank these outcomes so the developer can resolve competing requests without treating every feature as equally important.
List content, functions and ownership
Prepare a page list, languages, forms and integrations. Identify who supplies approved text, photographs and access to existing systems. Mark must-have requirements separately from later ideas. Include domain ownership, editing needs and the person authorised to approve changes.
Make delivery reviewable
Define checkpoints for content, design and launch. For each function, write an observable test such as receiving a submitted enquiry in the correct inbox. Agree exclusions, handover files and support scope. Keep a numbered brief so later revisions have a clear cost and schedule impact.