To calculate the overall star rating and percentage breakdown by star, we don’t use a simple average. Instead, our system considers things like how recent a review is and if the reviewer bought the item on Amazon. It also analyses reviews to verify trustworthiness.
Most of the really good advice is now well known - "remove unnecessary words", "use active rather than passive tense." But in the detailed section, it is often dated, e.g. a reminder of how the word 'clever' applies to horses.