1. Extract single keywords or short phrases.
Leave out articles ("a," "an," and "the"), prepositions or verb phrases (like "on," "in," "going to"), verbs (action words), and both adverbs and adjectives (descriptive words) when selecting keywords. Instead, focus on the nouns in your sentence.
It's important to note that you do not want to use complete sentences when you start searching for sources. Catalogs and databases struggle to identify relevant terms from full sentences, which is why you have to isolate those words in advance.
2. Experiment with synonyms.
Try to think of other words that have the same meaning as your keywords. For example, if you started with the phrase "global warming," you might also want to try searching for "climate change." An online or print thesaurus can help identify useful synonyms.
3. Brainstorm related terms or subtopics.
It helps to think of other words and phrases that relate to your topic. This can be especially helpful if you are having trouble identifying good keywords or if you need to refine your research focus. For example, if your initial topic was global warming, you might want to consider searching "acid rain," "air pollution," or "biodiversity." Related terms are often more specific or less specific than your initial search terms. Each combination will change the number, type, and relevance of your search results.