I'd look into how rescues work, even ask a rescue if they can do a courtesy listing for you. Rescues know the ins and outs of finding good homes for dogs, and there are lots of ins and outs. The person who assures you they'll take great care of your dog may mean "by putting her outside and leaving her there 24/7 because outside dogs, yay!" I would definitely charge some sort of rehoming fee, that will help weed out people looking for bait dogs and such. I would ask for references and actually call them, and I would drop the dog off at the home and do a home check at the same time. While there, look around, did they buy dog food for the dog? Are there toys and a doggie bed? A leash and a water bowl? Dedicated owners will have all that ready and waiting, and you want a dedicated owner.