*Pay attention to your curiosity as you begin your background reading. Jot down your questions as you go. "Why" and "how" tend to work better than "who" and "when" questions.
*Follow leads. Encounter an interesting person or odd occurrence? Find a bit of irony or a strange cause and effect relationship? Pay attention to these and pursue them, doing a bit of research to fill in some details.
*Go narrow and deep. Broad topics make research difficult and dull. Choose a narrow topic where you can take on real questions.
For example: Interested in the US boycott of the Moscow Olympics? Rather than look at why the United States pulled out -- a topic zillions of historians have tackled and one you cannot analyze well in a ten page paper -- how about looking at the response of athletes? Pursuing that lead, you might notice that boxer Muhammad Ali supported and was a spokesman for the boycott before changing his mind. Maybe you look at Ali's experience and change of heart? Perhaps you look at a few athletes who, despite their obvious interest in competing, supported President Carter's decision? What motivated them to back Carter?
*Following a trail can lead you to a narrow your topic and hone a more interesting question.