DCMI provides you with an introductory content on Metadata Basics including what metadata is, what defines Dublin Core metadata, explanation of application profiles, shared semantics, linked data and vocabularies. DCMI has also series of informative webinars on different aspects of the topic.
Ideally, repositories will expose their metadata using common schema and vocabularies so that the records can be standardized, and aggregated by repository networks. In turn, these networks can develop more useful services with the metadata, such as tracking open access, discovery of content, and analytics.
Currently most repositories expose their metadata through the Open Archives Initiative - Protocol for Metadata Harvesting (OAI-PMH). This protocol allows the repository to use a variety of metadata profiles, in addition to the simple OAI-DC metadata format based on Dublin Core. For generic data repositories, the DataCite metadata schema is the most widely used. Domain-based metadata schemas may also be used by repositories that specialize in collecting content from a specific discipline.
In addition, there are regional guidelines for repositories defined by certain repoistory networks, such as LA Referencia and OpenAIRE require the adoption of certain specific metadata elements and vocabularies in order to provide services based on the metadata they aggregate.
OpenAIRE Guidelines for Literature Repository Managers v4 describe the application profile for Literature Repository managers to be compatible with OpenAIRE.
Bielefeld Academic Search Engine (BASE) has compiled golden rules that are helpful to optimize OAI interface of the repository to assure fast and smooth indexing of the source in BASE.