Examples of topic mapping, mind maps, word clouds....
Develop a list of keywords, narrower terms, broader terms, phrases, and concepts that will be important to your research. If you aren't sure, start with one of the online encyclopedias, and see what kind of terms you find there on your topic.
If you are looking for books or articles that present argument or discussion of a topic, try this strategy:
your_topic AND controvers*
your_topic AND debate