Contact and meet the citizens that are going to star the project before writing it.

Apply for little calls as a pilot before going to bigger ones.

Being onto the field and participating in local events is what generates the most engagement. Don't allow that audience percieve your project as something far from their interests. Civic equipements, congresses, schools, etc.

Give something back (look after) to the participants to keep a high commitement: constant information about the project, access to privileged contents or events, gifts, draws, certificates, gamifications with reward systems...