Hello Steve, Thank you for coming to us with this. I found it helpful to have visuals, such as website/facebook page/leaflets, while explaining more to people about the cause, how it relates to the community, what it means to me to work on it. this mixture of visualization, personal experience, effect on community, and how they can help (solution) have been effective in gaining peoples interest in the cause, to ask more questions, and often have a list of interested volunteers. We actually have a detailed chapter on volunteerism, please follow the Hyperlink for more information.
Chapter 11. Recruiting and Training Volunteers
Good Luck,