The preliminary outline can serve as your road map for research.
How do you create a preliminary outline? First, realize that all research papers will start with an introduction and end with a conclusion. In between, there are usually three to five points that must be covered in order to answer the question sufficiently.
Suppose this is your research question: "Will stronger gun-control legislation protect lives?" Your preliminary outline might look something like this:
I. Introduction
II. Evidence that gun-control laws protect citizens
III. Evidence that gun-control laws have no effect on civic safety
IV. Analysis of effectiveness of current gun-control laws
V. Conclusion
As you search for books and articles on your topic, you can look for items that will support the various parts of your outline. You can even organize your research results by grouping items according to their usefulness for supporting the different points in your outline.