If that is the case for you, you need to follow the guidelines above to narrow the topic appropriately. The purpose of this activity is to find out what you already know on the topic. Doing brainstorming in a group is very helpful because several people will likely come up with a more substantial list than a single person. Having a list like this will be a big help when you begin to organize, but it helps here by giving you a list of ideas that need to be explored. Journalist Questions is another method that helps to generate areas of exploration and development.
Mapping is a technique much like brainstorming with a dominant visual element.
Be sure your topic will meet the demands of the assignment mode, if one is given. Part of getting started includes understanding what you are being asked to do. Your college compositions book should offer insights regarding the various modes and how to implement them successfully. Remember that modes are supposed to serve your message, not the other way around. Your organization and development will always be governed by your purpose and your audience.