Most dogs will circle back to the place they went missing from please continue to check or stay in the area. Put some of your dirty clothes out at the point of escape so he/she can smell their way back. If you can, fire up the grill and cook some hot dogs and bacon, and Liquid Smoke, dogs can't resist the smell. If you can't fire up a grill put out some rotisserie chicken with Liquid Smoke at the point of escape. Also get lots of flyers up right away and ask that people call with sightings but not to chase him/her. Put flyers in plastic page protectors so they don't get wet and ruined. Even if he/she is no longer at the point of the sighting, plot all sightings on a map so you can track their movements and patterns of travel and can trap more easily if necessary. Do not wash their toys or bedding and do NOT put them outside, instead put them in zip lock bags to preserve the scent so you also have some of their favorite things for scent lures if trapping is needed. If you have an electric fence turn it off and if you have a regular fence, open the gate. Contact a professional if more help is needed. Try Treasured Tails of MD if so.
Put out some dirty clothing or bedding for scent. Grill some bacon or hot dogs outside for scent. Post flyers within a 3 mile radius and include contact info. Ask people to take a picture of flyer. Not everyone is on FB. File Lost report with local shelter and police.