Most product page mistakes are not design failures. They are missing information. A shopper lands on your page with three or four specific questions, cannot answer one of them, and leaves without ever telling you why. Fix the information gaps first and the page...
The way to find a product to sell online is to run a filter, not to wait for an idea. You generate a wide list from places where real demand is already visible, cut it against fixed written criteria, then test the two or three survivors with a small amount of money...