Developing an effective search strategy requires a little bit of planning. This video from McMaster University shows you the process of creating search strings from your topic ideas.
Many databases, like library catalogs, will create search strings for you. Find the "advanced search" option, usually somewhere right next to the standard search box. Advanced search pages usually have drop-down boxes so you can tell the system how you want it to read your search terms, and you can usually add multiple lines for longer strings. You can also build your own search strings. More details about search strings and Boolean operators are in the second tab of this guide.
It's a good idea to keep track of which search terms and strings you've already used in which databases, and which results they returned, so that you don't repeat your efforts unnecessarily.
Some alternative keywords are obvious. Others, especially subject headings and other technical terms, may not be. When you are building and expanding your lists of synonyms, be encouraged to use the tools available in online resources.
Subject Headings can often turn up far more plentiful and relevant results than keywords can. Subject Headings are created by authors, publishers, and catalogers in order to describe the main subjects of a given book or resource. A couple ways to find good subject headings are:
Another way to find subject headings, and other technical terms, is to use the Thesaurus tools found in many databases, such as those hosted in Ebsco or ProQuest. To find the link to the database Thesaurus, select a particular database to search, then click on Advanced or Command Line search, and a link to the Thesaurus should appear on the page.