Keep records of your work throughout the process. Make notes of where you searched and your results from each step.
This will keep you from having to repeat steps and will help you recall what search terms you used. If you cannot find a definitive answer, you will be also able to report on what you did find and where you looked.
This research guide provides an overview of conducting case law research using Lexis, Westlaw, and Bloomberg Law, the three commercial databases most frequently used in law firms. This research guide covers how to find cases and how to verify that cases are still good law.
There are various free options for conducting case law research online, but many of these resources lack the case finding tools available on Westlaw, Lexis, or Bloomberg Law such as citators.
Please see the Library of Congress's How to Find Free Case Law Online research guide for more information about how to use the below resources.