WHO - who is affected by your topic. Don't just think of the focus of your topic but the people who are impacted in other ways. For instance, family members and employers.
WHAT - what is caused or affected by your topic. For instance, how much sleep you get might affect your success in college or success in the workplace.
WHEN - are you interested in the present or the past?
WHERE- are you only interested in the United States? Limiting your search to a geographic area is a powerful way to narrow your search.
WHY - why are you interested in this topic? Why should your classmate (or instructor) be interested too?