Conduct research. Use the Internet, or go to the local library to browse journals and books in your topic area. Look for sub-topics or current debates that you could use to narrow down your focus. Alternatively, search periodicals for recent events in the field, such as discoveries or breakthroughs.
Brainstorm the topic. Write down your research topic in the center of a sheet of paper. Write down as many related words and ideas as you can. Brainstorming crime, for example, will produce ideas like murder, theft, victims and prison. When you've finished, look at your answers and categorize them as best as you can. Collate words and ideas that are related, such as types of crime, prison sentences, effects on the victim or society in general. You can then investigate one or more of these narrower, more focused topics.
Focus on one aspect of the topic. This could be psychological, economic, social, cultural or political. For a research paper on eating disorders, for example, you could focus on the cost implications of treatment, or its emotional effects on patients.
Consider time and place. Another way to break down a topic is to focus on a particular time period, like the Middle Ages, the 19th century or even the 1980s. A research paper on women's health, for example, can be narrowed to women's sexual health in the 1700s. You can also narrow the topic further with geographical boundaries, such as women's sexual health in the 1700s in England.
Focus on a social group. Narrow your topic area down to include a specific gender, age and cultural or ethnic background. A paper on eating disorders, for example, could be narrowed down to focus on children, teenagers, African-American women or Chinese men. You can also compare and contrast between two or more groups throughout your research.