Most research starts with what is called a 'literature review'.
If you looked at the previous guide (Finding your research question) you'll know it ended with Julia describing how she starts a literature review.
Doing a literature review is a way of uncovering what we already know about a topic. Researchers need to do this for two reasons: first, a lot is already known about most topics, and we want to be sure that we are researching a novel question. Second, we want to get a balanced view of what is known, rather than jumping in and relying on the first pieces of information we find.
How do you start to find relevant material? Most researchers start by assembling a collection of key words that relate to the topic.
How do you define those all-important key words?