The Subject Headings Manual and the Library of Congress Subject Headings provide guidance for the choice and formulation of subject headings.  H 2230 deals specifically with visual materials.

Subject headings should be assigned to both non-fiction and fiction works.  If one or two specific headings are not sufficient to provide access to the major topics of the work, then one or two broad headings should be used to cover the overall subject matter.  In some instances, there may be no appropriate subject headings.

For guidance on applying genre and form terms, a standard list, such as The Moving Image Genre-Form Guide or Moving Image Materials: Genre Terms, may be used.

See also:

Appendix A:  Part I.  A1. Added entries at the second level of cataloging

Appendix A:  Part I.  Name, Subject, and Genre Heading Access Points

Appendix A:  Access Points