You should check out for some inspiration

List a few of your more interesting things or most wanted items. List things such as Antiques, tools, or collectibles. Not too many though just 3-4 will do. Give address, and directions if hard to find. Also post definite hours, You might say something like, everything goes, or great prices, or dont miss this…
Also make sure that you post bright clear readable signs at the site, and up the street so that people can find it easily and they have plenty of time to stop after they see the signs. You may try ballons at the site also.