Topic suggestions from Opposing Viewpoints
Place your topic within its broader and/or narrower contexts:
World History → Ancient History → Ancient Rome → Emperors → Julius Cesar
Narrow your topic to one that is manageable. Example of Mind Map from Credo Reference
Remember that research is not simply gathering information. You should always be attempting to solve a problem or to answer a question: "Research is not a compilation exercise but an opportunity to address an issue or solve a problem" (Badke "Creating Research Questions").