W3C has released Data on the Web Best Practices.
Here's an excerpt from the announcement:
W3C is delighted to publish its Data on the Web Best Practices as a Recommendation. The document offers 35 Best Practices for sharing data, openly or not, in a way that maximizes the potential of the Web as a data platform rather than simply as a way to send data from A to B. The Best Practices are prescriptive in their intended outcomes but not in how those outcomes are achieved. They cover everything from the basics (provide metadata!) through nuance (provide structural metadata), to topics like licensing, provenance and basic information on providing APIs through to more advanced topics like data archiving, data enrichment and republishing data.