If you have already found a relevant case for your topic, there are three techniques that you can use to find other relevant cases.
View the list of cases that the court cited in its decision. These cases will be found in the Table of Authorities (TOA).
In Westlaw, the case text includes a tab for the TOA:
In Lexis Advance, the TOA is located within the Shepard's report. (See the Citators page of this guide for more information on Shepard's.) First click on "Shepardize this document."
Then, select "Table of Authorities" to find a list of cases cited by your case.
BLAW also includes a tab for the TOA within the main text of the case:
Use the headnotes (topics applied to your case by the database's editorial staff) to find other cases which discuss the same legal issue as your case.
The West Key Number System allows you to easily find other cases that have been categorized into the same issue(s) as your case. To find these cases, click on the key number link(s), which appear near the top of the case:
Within your case, first select the "Go to" drop-down menu and choose LexisNexis Headnotes:
Then, you can click on the links provided to find more cases (and other documents) that have been categorized with the headnote:
Bloomberg currently only includes headnotes for a limited number of topic areas: Communications Law, Employment, Environmental Law, Health, Intellectual Property, Labor, and Trade. See this video for more details (5:48):