Keywords and metadata
To make sure that your data is findable (even if access to the data themselves are restricted) you should use a research data repository.
Trusted repositories use the appropriate metadata standards, and discipline-specific data repositories are usually supported by funders or the community (so have tailored metdata fields and descriptions). Always complete as many fields as you can and use keywords associated with your data, project and discipline to aid discoverability.
Coming to the end of a large project and there are no protocols? Then add the project name and any reference number as additional information in all related items (often deposited by different sub groups/ projects and collaborators) and use the same keywords so that the records can be connected. .
Data from large projects may also be deposited elsewhere. In this case, creating a metadata-only record in the Liverpool Data Catalogue, with the appropriate keywords, will also ensure that all related items are discoverable.