Most assignments are not open ended. Chances are your instructor has given you a specific set of guidelines that help focus your research in the assignment's requirements. Always read the assignment instructions carefully. Chances are you won't do well on the assignment, no matter how well written or researched your paper is, if you don't follow the instructions.
While understanding the assignment and it's requirements is the first step, there's still more to do before you actually start writing your paper. Part of choosing your topic means starting broadly and focusing that down to a more manageable topic.
Do: Your assignment is your starting point. Keep this is mind as you begin to think of background sources to get additional ideas and questions for your topic.
Don't: Decide on your position too early in the research process. Doing so will limit the effectiveness of your research and writing by backing yourself into a corner and being limited in the sources you can find and use. Remember, developing a topic and focus is NOT the same thing as choosing a position.
A concept map is a great way to help organize terms and ideas you come across as you do your research. Using a concept map will allow you to spot connections between ideas and focus in on the aspect you want to write about. Take a look at the concept map below about active learning.
In this example, the central idea of active learning is broad while the related topics, such as problem based learning or blended learning, are more narrow in their focus. Using this concept map, you may discover that you want to explore the benefits of using constructivist teaching methods versus traditional education methods.