Alexandra Stam, from FORS, explained basic concepts of open science and importance of data sharing according to FAIR principles, pointed out new requirements from funders and journals, and explained key data management skills for research and how day-to-day data management is different than data management planning. She also described the main challenges to data sharing in social sciences: what data to share versus to preserve, how to handle ethical issues, how to ensure data security and where to share data. Presentation was delivered at "Data management for open science" workshop, held on 4th December 2019 at the Faculty of Humanities and Social Sciences, University of Zagreb (FFZG), Croatia, during the first official presentation of CROSSDA, the Croatian Social Science Data Archive as a national public service and service provider for CESSDA ERIC.