Craft
The language of catalogue copy
Catalogue description is a constrained form with its own conventions. Judged as advertising it looks flat; judged on its own terms it is doing something harder.
A catalogue description has perhaps forty words to tell a reader what a thing is, what it is made of, what it will do, and how it differs from the item beside it. It cannot build atmosphere, because atmosphere takes space it does not have, and because the item next door is competing for the same decision. The result is a prose form that rewards precision and punishes flourish more directly than almost any other commercial writing.
Facts first, in a fixed order
Good catalogue copy tends to follow a stable order: what it is, what it is made of, the dimension that matters most, then the distinguishing feature. The order is fixed on purpose. A reader comparing six blocks learns the pattern after two of them and can then jump directly to the fourth element in each. Varying the order for the sake of variety destroys that advantage and is the most common self-inflicted wound in the form.
Adjectives that survive
Not all description is measurement. The useful adjectives are the ones that predict experience: stiff, close-grained, matt, unlined, hand-finished. The useless ones are the ones that describe the writer's enthusiasm: superb, stunning, unbeatable. A rough test is whether the word could be contradicted by the parcel when it arrives. If it cannot be contradicted, it is carrying no information.
The specification line
Separating the specification from the description is worth the space it costs. It lets the prose stay readable while the numbers stay comparable, and it makes omissions visible. A description can quietly avoid mentioning weight; a specification line with a weight column cannot. Readers who use catalogues heavily read the specification lines first and the prose only to break a tie.
Honesty is a design decision
The temptation in any range is to write around the weaknesses of the cheaper items. It is usually a mistake, and not only for ethical reasons. A range where every item is described as excellent gives the reader no way to choose, so the reader either buys the cheapest or buys nothing. Saying plainly that one version is lighter and less durable is what makes the heavier version sell, and it is what makes the catalogue worth consulting a second time.
Writing to length
Because the block is fixed, the description has to fit exactly, and drafting long then cutting is far more reliable than trying to hit the length first. Most descriptions improve under a third cut; the words that go are almost always the connective ones. What remains reads clipped on its own and perfectly natural in the grid, which is the only place it will ever be read.