1) Tell me who the players are. What groups of people or individuals in both countries are using their power, or responding to power? What did they do? Be specific, ie 'industrial workers in Chicago," not "the average person"; "they had a sit-down strike," not "they protested.")
2) Tell me the key things that were going on between the United States and your country during the time you're going to write about. Try to be as specific as you can with dates and events.
3) Tell me what you think. Based on what you've found so far, what have you noticed about this relationship? Would you argue that the relationship between these two countries is an imperial one, or something else? If something else, how would you define that something else?
After you've interviewed eachother, write a 'revised brainstorm' that describes how you've narrowed your topic, the heart of the story you're going to tell, and what you need to find in your additional sources.