After choosing the subject for your extended essay, the next step in the research process is to define what your research is going to focus on - the topic.
At this stage you need to explore:
Undertake some general reading around the issue. Questions you must consider at this stage are:
Conduct an initial background search to help find a focus for your research and discover possible keywords & synonyms to use as search terms when looking for relevant information. Generating initial research questions can help with this process.
These links may help:
Say your question is this:
How and why have explanations of the Cuban Missile Crisis changed since 1962?
Step One: Identify the key concepts and define/explain them. (What key concept is implied in this question but not explicitly stated?)
Step Two: Think of synonyms for each.
Step Three: Start a mind map of these concepts and add ideas, facts etc... that relate. Keeping adding to it as you learn more. Take your keywords for searching from this mind map.