While you are gaining background information, consider how you might focus your topic. Restate your topic more concisely based on information you have gathered. Stating your topic as a question is often helpful.
For example, our sample topic so far is pretty general: I want to write about endangered species.
After generating some questions about the topic and doing some background reading in encyclopedias, these discoveries were made:
So, after considering that I am only going to write a short 3-5 page paper, I may decide to limit my topic to just the United States. A more focused research question might be: "What is the history of the endangered species list in the United States?"