This guide evaluates the experience of involving older people in a research study that explored the age-friendliness of three areas of Manchester. It offers practical tips and critical reflections to help rethink how older people can be involved in research and social action to improve the physical and social environment of their neighbourhood. For the project a group 18 older residents were recruited and trained in designing interview questions, interviewing, data collection, and sharing the findings. The guide outlines the aims of the study, the methodology of the research and a summary of research activities undertaken. It then covers: what 'age-friendly means'; the co-researchers' motivations to participate in the study; the advantages and challenges of involving older residents; skills and knowledge acquired through the project; key findings; and suggested improvements to the age-friendliness of neighbourhoods. The guide includes contributions from older co-interviewers and representatives of community organisations who were involved in the project. The guide concludes by suggesting three principles for developing age-friendly neighbourhoods: that they should empower older people and enable social participation; they are a reminder about the rights of all citizens to full use of resources in their neighbourhood; and the importance of recognising both the social and physical dimensions which make up age-friendly communities.