Make a few edits to homepage to make it look more like a marketplace, maybe incorporate some social media follow options.
Insert logo banners on homepage
Center homepage on header
Enable anyone to create an account and sell there items at the best price, we just review postings
Create a terms and conditions option for both listing an item and purchasing an item and creating an account
Ask more questions when registering similar to ebay forum, sell an item similar to this page [login to view URL]