Optimizing a product description for SEO is the best way to ensure the right customers find your products. Your chosen keywords and phrases should be specific enough to be competitive and rank, but not so broad that no one naturally searches for them. So, make sure you do keyword research before you start (tools like AHrefs and SEMrush are useful here).
Then, incorporate your keywords throughout, using them in the meta data, alt text, headings, and body of the text. Make sure you use them naturally though, so you don’t compromise readability or the user experience.