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.