When I research for school, I usually develop a broad topic in my mind and check out several books on that topic. When I read these books, I am able to develop a conclusion, idea or hypothesis about that topic, and narrow it for a research paper. Once my topic is narrowed I will then return to the library and check out more books geared specifically towards my topic.
When I am doing professional research, I have learned to use the older and more experienced teachers and administrators in my building, and to seek out contradicting ideas so that I may come to a conclusion myself. I usually stay away from professional articles because of their lack of pragmatic applicability to a living breathing student body in a given context.