For several years, the European Commission has worked to improve access to scientific results, including data. To do so, they have developed the FAIR data guiding principles, which states that data should be findable, accessible, interoperable and reusable. Details of such principles are given below, as well as useful related resources:
Findable: (meta)data should be easily findable by humans and machines, which means that
F1. (Meta)data are assigned a globally unique and persistent identifier
F2. Data are described with rich metadata
F3. Metadata clearly and explicitly include the identifier of the data they describe
F4. (Meta)data are registered or indexed in a searchable resource
Accessible: Access to the data should be easy (with authentification, or autorizations restriction if needed), which means that
A1. (Meta)data are retrievable by their identifier using a standardised communications protocol
A1.1 The protocol is open, free, and universally implementable
A1.2 The protocol allows for an authentication and authorisation procedure, where necessary
A2. Metadata are accessible, even when the data are no longer available
Interoperable: Interoperability means allowing data exchange and re-use between researchers, institutions, organisations, countries etc. (i.e. adhering to standards for formats, as much as possible compliant with available (open) software applications, and in particular facilitating re-combinations with different datasets from different origins).
I1. (Meta)data use a formal, accessible, shared, and broadly applicable language for knowledge representation.
I2. (Meta)data use vocabularies that follow FAIR principles
I3. (Meta)data include qualified references to other (meta)data
Reusable: reuse of data should be possible. To do so, data should be properly described and documented (in order to be replicated, combined with other, etc.)
R1. Meta(data) are richly described with a plurality of accurate and relevant attributes
R1.1. (Meta)data are released with a clear and accessible data usage license
R1.2. (Meta)data are associated with detailed provenance
R1.3. (Meta)data meet domain-relevant community standards
Useful resources:
Wilkinson et al. (2016), "The FAIR Guiding Principles for scientific data management and stewardship", Scientifi Data, 9p. DOI: 10.1038/sdata.2016.18 https://www.nature.com/articles/sdata201618
European Commission: Turning FAIR into reality: final report: https://ec.europa.eu/info/sites/info/files/turning_fair_into_reality_1.pdf
JISC report: FAIR in practice: https://www.jisc.ac.uk/reports/fair-in-practice