Build relationships between the parts
Decide which elements remain consistent and which are allowed to change. A stable information grid can support an expressive image language.
Give every element a job. A supporting colour should not have to serve as a small text colour if its contrast makes that difficult.
Test the awkward formats
Try a long headline, a narrow label, an image without a perfect crop and a page with less content than expected. These reveal the limits of a system.
A useful guideline shows both a strong example and the reason it works, so people can adapt it when the exact layout is unavailable.
Handover is part of the design
Organize files by use, explain the type hierarchy and document the practical limits of images and marks. A tidy archive is only useful if its contents can be understood.
List unresolved production and implementation questions. Calling out an unknown is more helpful than presenting an illustrative mockup as a finished operational asset.
