When you are diving into a research-based project, it's easy to drown in all of the amazing material you unearth. Hard won facts and primary documents found after long months of searching can have such an enormous impact on your work. But these shiny bits of aha can also weigh down a project. They can make it easy to forget that despite the level of research your work requires, you are still trying to tell a story. Facts and evidence are, of course, important. All of that amazing research you've done is a nonfiction project's skeleton--the solid stuff that holds it together. But the story is its flesh and both aspects are necessary for a fully formed narrative.
If you're worried that your project is all bone and no meat, or perhaps has an extra head, try this writing exercise:
Write out the story you are trying tell without consulting any of your sources or research notes; don't use any quotes or even contemplate a footnote. Your aim is to be a comprehensive and brief as possible. Once you've got it all down, set it aside for a day or two. Go to the beach, or work in your garden (it's homework, I insist). When you return to your desk, reread this condensed version of your story. Then ask yourself some hard questions:
Does a clear narrative emerge? Is your subject fully formed? What can or can't you tell your reader about your subject?
What is the larger story you want to tell? Is that larger picture clear?
What is central to your story? What is not?
Are your answers to the above questions the same when you consider your larger project?