Once you have identified your main topic you will have to identify specific items within it to focus your research. The key to this step is to read a lot of basic information. You have to understand the overall depth of your topic in order to understand ways in which you can focus your research.
You will need to assemble a list of keywords and phrases that can be used in secondary sources, such as journal articles. Broad overview terms such as China will yield millions of hits and provide no focus to your research.
Look for terms you can build into Boolean searches. “China” works when you add it to the expression “Ministry of Education.” Looking for either separately finds too much irrelevant information.