All sales begin with some form of advertising.
To build sales, this advertising must be seen or heard by potential buyers, and cause them to react to the advertising in some way. Whether your ad is a success or failure reverts back to the ad itself. Any ad that causes the reader to only pause in their thinking, and does not persuade the reader to act immediately, is not going to be a successful ad. I have tested many of those above with astounding success. Target your classified ad to the audience interested in your product or service.