This handbook provides a practical, discipline-oriented guide for implementing FAIR (Findable, Accessible, Interoperable, Reusable) principles in Earth and Environmental Sciences (EES). Addressing the gap between abstract guidelines and concrete practice, it offers specific recommendations for researchers at all career stages to improve the visibility and reusability of their datasets. The document details the specificities of EES data, including the critical management of geographic dimensions (coordinate reference systems), temporal scales (deep-time representations beyond ISO 8601), and domain-specific vocabularies. It also addresses ethical considerations regarding field data collected on Indigenous lands, integrating the CARE principles alongside FAIR. Key features include: Concrete actions for each FAIR sub-principle tailored to geosciences; A curated list of specialized EES data repositories and platforms; Guidance on metadata standards (e.g., GeoSciML, ISO 19115) and open formats. This resource can serve as a foundation for developing Data Management Plans (DMP) and ensuring compliance with funder requirements while promoting open science practices. Acknowledgements: The following people are acknowledged for their valuable feedback on an earlier version of this handbook: Luca Caricchi, Sébastien Castelltort, Noemi Duperron, Audrey Lambiel, Joël Ruch, Anouk Santos & Niklas Werner.