They say every picture tells a story. I would second that and add: every book entry should be story-focussed. There is nothing more dispiriting than perusing booksellers' catalogues that are mere agglomerations of facts, culled from Wikipedia or publishers' websites.
Real magic tends to happen when collating technical details, book condition, provenance, edition on hand in relation to prior printings, importance of said volume, a brief précis (if the work warrants it), interspersed with review blurbs, all help build a holistic book presentation. When you unearth in your research relevant facts, such as how the book came to be written, where it sits in the writer's corpus, what is the pre-dominant, orthodox view of what the writer is trying to convey, together with any dissenting or minority critiques, and then build the whole into an argument, a story. When you enhance the reader's appreciation and understanding of the offered work. Any information you may wish to impart is much better retained and recalled if presented in story form. This is how we humans have made sense of our surroundings since time immemorial.
Accuracy of description trumps everything. If you come across a 'fact' about a book, such as a prize nomination or indeed an award, check against original sources, to make sure you get it right. A sliver of your personality, such as your innate sense of humour, 'inside knowledge', even shop talk might occasionally break through. But these must not overwhelm the book description, which should invariably err on the academic, fact-based side. Unsupported and sweeping statements are best avoided.
They also say "less is more". One should always be succinct in book descriptions, avoiding jargon and favouring accepted technical terminology. Such as that used in John Carter's trade bible, ABC for Book Collectors. Cull, cull, cull! As Blaise Pascal famously wrote in his Lettres Provinciales: "I would have written a shorter letter, but I did not have the time."
Didactic as the above statements may all seem, they are primarily descriptive: of book descriptions meant for reading.