A practical guide designed to assist those organising and participating in a citizen science project to get the most out of the experience. The guide will enable you to have the skills to ensure a project is well set up from the start, is able to communicate to its stakeholders and citizens, manage its data and outputs, and overall ensure research benefits. The guide has been compiled by the LIBER Citizen Science Working Group and pulls on the generous contributions of the open science community. The book is intended as a short guide and will be approximately one hundred pages in length. The publication will be produced as multi-format and multi-channel (print-on-demand, PDF, Webbook, website, eBook, and as a Jupyter Book) and will be technically designed for reuse, for example in community translations or in MOOCs. Book sections will be released incrementally as they are ready. Ideally, the book will become a community-owned publication with regular updates.