Project descriptions, often found on citizen science platforms, are the gateway for citizen scientists to engage with projects. They provide the first glimpse into what a selected project is about, how it operates and how participants can contribute to its efforts. As such, project descriptions play a key role in attracting volunteers to citizen science projects. For this reason, the importance of an engaging, clear and concise project description really cannot be overstated. In this document you will find a 10-step template to help you write an attractive project description. It will guide you regarding the main topics and types of information to include in your description, offer explanations and suggestions for items to consider in each step and provide examples from two hypothetical project descriptions we prepared. This template is an output of our research in CS Track, which involved analyzing citizen science project descriptions to find out what can be learnt and understood from them. In the course of this work, we discovered that many project descriptions do not clearly articulate their project goals or the impact it may have on the scientific community, on the individuals participating in it, and on societal issues (such as public administration, policy-making or conservation efforts). We also noticed that often project descriptions do not explain which tasks citizen scientists will be asked to perform, what the time commitment may be and what prior knowledge or skills are required of them. In short, we pooled our findings to design an evidence-based template for writing citizen science project descriptions. Enjoy!