Beside using effective keywords as metadata to tag your content (documents, pictures, emails), what can you do to improve information “findability”?

narrowing down search area by using additional criteria such as User/Author ,and date of publish.

for structured data , utilize information classification , though this is a security requirements however it has the benefit of defining the information search criteria based on content and usage.

for unstructured data, try using objectives of usage as a start point , someone looking at totally unstructured data must have an idea first to produce , identifying the idea minimizes the scope of searching

probably you need a data scientist to anser this !