Look at an encyclopedia for general information on your topic and note interesting facts/ideas.
Ask yourself the following questions:
Who is my audience? (Choose a topic that will be interesting to your audience.)
Will my topic fit the assignment? Is my topic still too broad for the length of the paper, speech, etc.?
What kind of information do I need to fulfill the assignment? A brief summary, journal articles, books, essays, encyclopedia articles, statistics? Can I locate these types of research materials for my topic?