Traditional biodiversity monitoring by professionals can be time-consuming and resource-intensive, and many habitats and species remain understudied and data deficient. Citizen Science (CS) and DNA-based monitoring are helping to fill these gaps by expanding the scale and impact of biodiversity monitoring. CS, or community science, involves members of the public in scientific research. It offers opportunities to build skills, improve wellbeing, and foster stronger connections with nature. DNA-based monitoring can detect species that are difficult to survey and help track how species distribution and ecosystem health and function change over time. This guide introduces CS and DNA-based monitoring, demonstrates how the two approaches can work together (CS x DNA), and provides practical advice on project design, volunteer involvement, training, and communication. The CS x DNA project, Genepools (Rees et al., 2023), is used to illustrate project design from start to finish, and we also explore future opportunities and challenges for this emerging approach. This document aims to facilitate crossover between these monitoring approaches and provides high-level advice for those wishing to use DNA-based methods in projects with volunteer involvement. We hope it will inspire collaborations between CS and DNA practitioners to drive better outcomes for people and nature.