What are some synonyms for your topic?
Writers and researchers often use different words that have approximately the same meaning. Articles about middle and high school students may refer to them as teenagers (teens), adolescents, or youth. In these cases, the boolean operator OR can be very useful.
Look at this example:
What words are you using that might be indexed using different forms of the words?
For example, if you search for "education", you may fail to retrieve valuable resources which use the words educator, educate, or educating. Some search engines allow you to enter a truncated word using a special symbol like ? or *.
Truncation has its own limitations, though. For example, if you search for "librar?", you will retrieve sources pertaining to libraries and librarians, as well as the those using the word "library". However, if you search for "libr?", you will also retrieve information about the sign of the Zodiac: Libra and operatic librettos.
Where will you search?
To avoid wasting valuable time, it is very important to consider thoughtfully which Internet search engine is likely to produce the most useful results; see the section Deciding Where to Search.