The market is always changing, and your product descriptions must change as well. The most important ingredient for a great product description is adaptability.
Take note of stand out phrases that may be working for your competitors. Take a look at search engine rankings to see what is working in your market. Most importantly, listen to your customers on social media and on industry message boards. More often than not, you will gain some insight directly from your prospects as to what they want your product description to look like.
There is no single technique that will make your product descriptions go from zero to hero overnight. All of the techniques mentioned above work in tandem to improve visibility and readability. If you constantly improve your product descriptions based on the needs of your customers, your online store will have a greater chance of moving that inventory.