A research paper should thoroughly develop a limited topic. The paper should be narrow and deep rather than broad and shallow. Therefore, as you read through books and articles, look for ways to limit your general topic.
For instance, as Sonya read materials on the general topic “parenting,” she chose to limit her topic to the particular problems of parents raising children in today's culture. She then decided to limit it even more by focusing on what successful parents do to deal with those challenges. To take other examples, the general topic “drug abuse” might be narrowed to “successful drug treatment programs for adolescents.” After reading about the worldwide problem of overpopulation, you might decide to limit your paper to the birth control policies enforced by the Chinese government.