I've recently started to follow this instruction from Zazzle:
"Description
Your design descriptions is a great opportunity to let your customers know the story behind your art, and an opportunity to help your customers understand what makes your design unique and worthy of their purchase over the others. It's also a great space for you to detail any interesting use cases, as well as customization tips, that you may have intended with your design.
One important thing to note is that search engines, such as Google, pay heavy attention to your design descriptions. So in order to ensure the best chances in surfacing within Google’s search results pages, you'll want to make sure that each of your products have unique and lengthy descriptions for Google to crawl. And don’t forget to include those relevant keywords in your descriptions, they will definitely help your chances of getting found."
More info here:
https://help.zazzle.com/hc/en-us/articles/115000373127-Title-Description-Tagging-Best-Practices
