Keep in mind the potential members' viewpoint. When developing ads, consider what would attract an applicant to the program before the actual program details. That's not to say details don't attract - just that they may boggle the mind if they come before applicants know what members might do or get from service. Consider the last time you committed yourself to a year-long project. Most research tells us that personal persuasion or contact does the trick.
Applicants like to talk to people who have gone through the experience.
Plan your recruitment timeline from the perspective of the applicant. It is hard to commit to something with only a few weeks' notice. Follow up on people who request applications. Provide more information about the program. Offer suggestions for completing the application.