I have posted my listing routinely to sites such as Facebook, Craigslist, Zillow and Land Search but still have not been able to find a buyer for the lot.

As a General Contractor myself here in east central Texas, I can tell you that connecting with local GCs via Facebook groups can be incredibly helpful.

All of these are posted on our local real estate facebook groups.In any of these events, you will meet like minded entrepreneurs who are also looking to grow. 

Even facebook might have some good local groups for you.

Try and join a few local Facebook pages and connect with locals who are in the house hacking business. 

Other areas to check would be local real estate meetups (check BP Events & Meetups, Eventbrite, Meetup.com) and local DC Facebook groups as well.

There are often local Facebook groups for specific strategies 

Hi everyone,Last week, I was pulling rent comps to prepare renewal offers using my typical process: starting on Ręntometēr or Rēntcast for a rough idea of recently removed comps, then manually researching on platforms like Zillow, Apartments.com, and Facebook Marketplace.

On Facebook marketplace you have to call it an apartment since they don't have a commercial option.

Local Facebook groups can be a valuable resource when looking for a handyman.