Marginalized and vulnerable groups experience profound environmental and climate injustices, being disproportionately affected by these issues despite their minimal responsibility and coping resources. This disparity extends not just between countries but also within communities of the Global North. Additionally, these communities lack representative data and are excluded from Citizen Science (CS) initiatives, intensifying their injustices. Despite the potential benefits of CS, these initiatives often involve predominantly privileged individuals, excluding the very communities most impacted. This exclusion highlights the urgent need for inclusive practices in CS to address these injustices. In response to these challenges, this report presents a Blueprint for Inclusive CS Engagement Strategies. This blueprint, developed for the Urban ReLeaf project's six pilot cities, addresses the critical issue of inclusive engagement. Divided into four phases (Preparing, Planning, Interacting, and Monitoring for inclusion) and eight steps (Explore, Understand, Organise, Design, Recruit, Communicate, Engage, and Assess), the blueprint guides the cities through the process of engaging non-traditional citizens, especially those from vulnerable and marginalized groups, in CS activities. The blueprint is a comprehensive guide, detailing considerations and guidelines for each step. Additionally, this report shares the outcomes of Phase I of the blueprint: Preparing for inclusion. It provides insights from multistakeholder workshops held in each pilot city, offering visual summaries for personas associated with prioritized target groups and co-created campaign ideas. These tools empower the pilot cities in subsequent stages of the development of their observation and monitoring campaigns (T4.1) by facilitating informed decision-making and community engagement.