Sometimes it is hard to pick a topic for your research, but there are ways to make it easier!
Brainstorm back and forth with a friend. Think of at least five possibilities each that fit the assignment parameters.Make it fun, but set a deadline for picking something.
Pick a topic that interests you. You'll be spending time reading and thinking about this topic for a while, so being genuinely curious about your topic will help lead to a successful project.
Match your topic to the scope of the assignment. For example, "underage drinking" may be too large of a topic for a 2-page paper. You can narrow your topic by adding other components, such as a time period or location. "Underage drinking on college campuses" or "depression and underage drinking" are more specific.
Ask a question. What questions exist that you genuinely want an answer to? This may not be necessary every time, but asking a question can be a helpful way to frame your research. "Has underage drinking increased in the past twenty years?" and "How does the media represent underage drinking?" are two very different approaches to the same general topic.
Make sure your topic fits the assignment requirements. Reread the assignment and if you're not sure, check with your instructor.