Small commitments lead to big ones. Start by getting the shop owner involved in a visit. Then ask them to sign a form stating changes they will make. Feedback and follow-up are important. Feedback gives people cues about the impacts of their behavior changes.
Additional contact is also very important in motivating people to stick with a task.
People will listen first to their friends or relatives, or others they see as credible. What they hear at a dinner party will have more weight than a comprehensive data summary. Change agents and role models are important. A few people in a group will typically adopt innovative ideas and behaviors first, and spread them through the group. Find these people and help them successfully adopt a new behavior.