If you want to show up in the search engines, you should definitely check out this guide by Kissmetrics.

Due to the dynamic nature of marketplace listing pages, we recommend that marketplace owners focus their SEO efforts on the marketplace blog. Specifically we suggest creating a pipeline of high quality, keyword rich content.

According to Quicksprout, "Content marketing is the cheapest and most effective way to do SEO these days. Not only does writing high quality content produce links at a quicker pace than building them manually, but it’s also cheaper." 

So what are you going to do? Start generating content.