Many different techniques are available to observe and quantify ecosystem functions and services provided by grasslands. Measurements need to be analysed and integrated to translate data into management recommendations for adoption in sustainable grassland management. Here, we provide an overview of techniques available to collect data about grasslands. Different spatio-temporal scales require different modes of data collection to capture grassland dynamics. Examples are provided, e.g., how high temporal resolution measurements of greenhouse gas exchange are used to quantify soil carbon sequestration and detect trade-offs between C sequestration and N2O losses; how image analyses help in restoration projects; how remote sensing is used to improve grassland farming; and how models help predicting biomass production and long-term carbon sequestration rates. The benefits of FAIR (Findability, Accessibility, Interoperability, and Reusability) data sharing as well as strengths and weaknesses of techniques are addressed, management options outlined and gaps in knowledge identified.