#5: Do you have good structure for the information in each product item in the list?
All product items should have the same information (title, price, reviews, short description, etc). There should be enough white-space between these entities to make it scannable, readable and easy to compare between products in the list.
Good structure of each product item simplifies the perception of information. Bad structure and cluttered design make users to spend more time to understand it and increase cognitive load.

Bad example:
You can see here each title contains product details, so users will need to read the entire title and then break it down into separate components to determine its relevance. Also all elements are closed to each other, there are no white-space between product titles, reviews, price, shipping information. As a result, the whole interface looks very cluttered.

Good example with a good structure of product items from Bulletproof:
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