1. Provide members of the public with information pertaining to federal agencies. Federal agencies are required to disclose any information requested under the FOIA unless it falls under one of nine exemptions that protect interests such as personal privacy, national security, and law enforcement. 
2. See https://www.foia.gov for any and all information related to FOIA including information about how and where to make a request under FOIA. In addition to the FOIA site maintained by the government, there are a host of other watchdog sites which are monitoring the agencies, courts, and cases in their handling of FOIA requests. Such sites include Justia for cases  https://dockets.justia.com/browse/noscat-13/nos-895; Epic.ORG for information and cases filed by EPIC in pursuit of information https://epic.org/foia/; The FOIA project for cases and information http://foiaproject.org/; U.S. DOJ https://www.justice.gov/oip/court-decisions-overview. 
3. Root around the sites then select one case of interest to you. Give us a summary of the case which includes the case name, request made, results of the case, and if you agree with the outcome. 
4. Remember that this topic may seem boring, but it's not. FOIA requests are made all the time on topics like autopsy photographs of Soldiers, intelligence information from Afghanistan, and arrest records.