First, carefully read and reflect on the question you've been presented with:
What are the relevant facts here? What is the relevant law? What is the relevant jurisdiction?
Once you have a basic understanding of the question, consider what form an answer might take:
Are you writing a short memo? A brief? A law review article? Something else entirely?
Then think practically:
How much time do you have to accomplish this?
Note that if you have received this assignment from, for example, a professor for whom you are a research assistant or a partner at your law firm, they may not give you all the pieces you need initially. You may have to ask additional questions - what we librarians call the "reference interview."
Library guides can be very helpful in answering legal research questions, especially when you are new to an area of law. Library guides will point you towards useful secondary sources and help you to locate relevant primary sources of law. The reference librarians here at HPU Law create and maintain a database of library guides on various topics, which can be found here: Kahn Law Library Research Guides
Primary authority is the law itself. It can take the form of constitutions, statutes, cases, and regulations. Once a relevant secondary source guides you to primary sources, it is time to start looking for specific authorities and organizing what you find.
One of the benefits of subscription-based legal research databases like Westlaw and Lexis is that they link statutes to relevant cases, regulations, and secondary sources. On Westlaw, the editors provide a "Notes of Decisions" tab that links different aspects of the statute to relevant cases. We recommend beginning with the Notes of Decisions, as they show key cases in a well-organized fashion. Another tab, "Citing References," links the statute to other cases, regulations, and secondary sources.
Cases are treated similarly, for example:
The case itself will contain citations to relevant cases, and the "Citing References" tab can be used to find cases and secondary sources that cite to this particular case.
At this point you will have moved from reading and reflection to secondary sources to primary sources on your given question. Note that legal research is an iterative process - you may have uncovered additional questions and sub-questions on your way to an answer.
It is vital to make sure that any primary sources you cite are still good law. The best way to do this is through Westlaw's KeyCite and Lexis' Shepards citators. These systems flag statutes, cases, and regulations that may no longer be good law.
Guides to using these systems are available here: