You might almost need to loss lead for years, paying people in some fashion to bring content. e.g., dress up listings similar to the way Airbnb sends out their photographer to shoot your place professionally, or Uber is subsidising drivers to establish a foothold.

If you did car sales (as a bad example), you could handle the entire process for customers - sending out a photographer, building the listing and researching an appropriate list price. Wear the costs until you have the brand established and can start to make money. That would probably be attractive to people who don't have time or aren't confident enough to do it all themselves.