Most product descriptions describe the product. The ones that sell describe the customer's day after buying it.

Lead with the outcome

Not "100% cotton" but "survives a Dhaka summer without fading". The specification is evidence; the outcome is the reason.

Answer the question they are about to ask

Every category has one. Clothing: will it fit? Electronics: is it genuine? Furniture: will it survive the delivery?

Keep it short

Three short paragraphs beat one long one. Mobile buyers scan; nobody reads a wall of text before deciding.