In terms of SEO, any selling platform is just a website. And you can only optimize what you have access to within that website. Unfortunately, that means that there is often only a few areas that you can improve upon within third party selling platforms like eBay and Etsy.
To make their platforms as user-friendly or universally accessible as possible, areas of code are often restricted. That restriction means that you can’t make a lot of changes that are often beneficial to SEO.
That’s not to say that there aren’t ways that you can influence the internal search engine of those platforms, but that’s a different marketing tactic than my world. My expertise is “traditional” SEO and search engines, like Google.
That being said, there are some basic best practices, regardless of platform.
Search engines can only read what they can rank. Therefore, make sure your titles are clear and specific. While there may be some advantages to stuffing titles with keywords for eBay’s algorithm, it may not have the same value in search engines.
For example, Google will only return a certain amount of words within the title of a search result. It used to average displaying up to 65 characters in a search result’s title. Now, it’s based on pixels. So if the words within your titles contain wider letters (letter W vs letter I) than less characters will fit. The less that is displayed before your product’s title is cut off, the less convincing or less clear your product offering is. Communicate clearly in product titles, or at least put the most important words first so they don’t get cut off.
Create call-to-action, too, in your product descriptions.
When you search something on Google, it will return the website’s domain, it’s page title, and a description. Many selling platforms use the product description to populate the search engine description. Take advantage of that. Phrase your description in a way that is enticing. Instead of a description that says “Red widget 1 and half inch width rounded corners,” I’d say “Act now for a red widget that solves problem xyz.”
There may be slight overlap in some areas that can influence ranking on a third party platform. Take backlinks for example. By getting other websites to link to your product listings, it may also contribute to the ranking popularity of that product.