A Farley File is a diary and aide-mémoire.  The easiest way to construct one is as a computer file arranged by Name.  Each entry should include the contact information (address, telephone number, email, etc.) if appropriate and known.  With the ubiquity of digital cameras a photograph could go in there as well.  The diary part is a running record of information regarding the person: spouse, children, hobbies, likes/dislikes, beliefs, questions, requests for information, & etc. and a record of interaction(s) with the person the Farley File is for.  Also an assessment and comments section could be in there.

A good idea is put people not met but important such as Congressional members, leaders and VIPs of all political parties, major businessmen, personnel within the organization, and so on.