I would start with improving the home page. I would have had no clue as to what the site is for if you haven't had explained it here. You could add a headline j

I would start with improving the home page. I would have had no clue as to what the site is for if you haven't had explained it here. You could add a headline just above the search bar that explains exactly what your site is for and why I should use it. It's hard work to come up with the right one but it's worth it. The search results page is really cramped up too. The design could really be improved. These are my thoughts on improving your marketplace. Note that they're not from a buyer's or seller's point of view but more from a design/conversion point of view. But I am sure that the buyers or sellers would be facing these problems when using the marketplace.