By using web directories and clicking on narrower and narrower sub-categories, you can get a clearer understanding of your topic and related topics. Try this before entering a keyword in a search engine. In order to understand this, first try one example together as a class with your teacher's help. Keep a written record of the string of categories you go through to get to the most specific keyword. Try a variety of Search Engines.
Search engines act like phonebooks for the internet.
Alta Vista and Lycos are examples. You type a keyword into the search box and press enter. A search robot scans thousands of websites to match your keywords with descriptions of sites. Remember that search engines cannot evaluate and judge for you. You may get thousands of matches for one word, and two completely different topics may use the same word.