The always-fascinating Jim Macdonald wrote a post some years back on the Absolute Write forums (you’re a member, right?) on the subject of becoming an instant expert in a subject.* There’s nothing hugely ground-breaking here, and yet… nobody ever really bothers to spell out this process, do they?
To summarize (though you should read his post): Go to your library. Start with recent kids’ books, to learn the basic concepts. Take those concepts to the thicker books, and drill down. Take notes. Specialize as you go, from broader concepts to more specific analysis, maybe even to original works (either primary documents or the original papers) Remember that for the writer, this is a directed process, for people who know from the outset what they want expertise in, and so you’re following a basic depth-first search strategy.
I suspect that people doing this sort of thing are going to want to start, not with a kid’s book, but with Wikipedia. That may be a mistake — there’s a LOT to be said for spending a day in the library doing this, with no distractions from Twitter or email or videos of cats. And there’s also a lot to be said for letting someone distill it down to an overview for you, letting them set aside the stuff that you’ll learn later but don’t need to know now. Wikipedia has a lot of information, which is both good and bad. It’s intended to be encyclopedic, which is not necessarily what you want at the outset. You need to pace yourself, or you will overstrain your brainmeats and start clicking on creepy pictures of Jimmy Wales. Once you do go to Wikipedia, though, I recommend spending time grabbing articles, then using Wikipedia’s book creator tool. The act of organizing something that you will then read offline will itself be useful. In that vein, Google Scholar becomes useful at a later stage in the process, when learning about more recent advances.
Finally, this is all also a lesson in satisficing: Part of the skill in researching for a writing project is knowing when you know enough to proceed. Nobody will see that first draft except you, it’s OK to be wrong in a few places, or to add sections of text like, “[Insert intelligent discussion of the properties of cyanide]” or “[Fix this later]”. Sure, to some extent it’s better to be right than wrong during that first draft, but if you’re like most people you’re 1) not going to have fully understood everything you just learned, and 2) are going to forget or misremember things. In other words, you’re likely to be wrong about a few things in that first draft anyway, and will be in a better position to fix it if you go into your editing process knowing that you got stuff wrong.
* I learned of this technique originally from Debra Doyle at VP, where I had the additional benefit of her insight into the process and the opportunity to talk about the differences between learning about science and about history. I still have the paper plate I took my notes on, too!