Reference and intention
Name the reference and state which parts matter: silhouette, length, surface, fit or a particular detail. Mark which elements are inspiration and which are required for the sample.
A measurable definition
Include measurement points and the intended size chart. Identify the base sample size and explain the wearer profile so changes can be evaluated against the same starting point.
An approval record
Keep each feedback round with the sample version and date. Consolidate material, measurements, trims and packing decisions before writing the approved specification.