Every writer has a different approach to researching a novel, and my approach is pretty half-assed. Yes, ladies and germs, I am no James Michner.
First of all, the reason I write fiction is because I like making shit up. There, I said it. Someone had to say it, right? Because if I have to hear one more super-serious writer drone on and on about "researching their novel" and "really getting a feel for the time and place" I'm going to have blow up their cats in my microwave, and I really don't want to have to do that. I like cats. They shouldn't have to be microwaved because some English department desk jockey literati wannabee thinks throwing in an extra two hundred pages of details they read on-line or in some other book somehow adds to the gravitas of their novel. It doesn't. It just bores the shit out of me. I want to read fiction. If I wanted to read non-fiction, I'd fucking read that, alright?
Somewhere along the literary line, a particular section of the American fiction reader has become convinced that every novel they read, like they cell phones they own, must serve at least ten different functions at once: they need to learn everything about horse racing while reading a romance that also teaches them a nice moral lesson, they need to become more aware of autism and rape and gay bullying while being pulled into the history of salt mining and a love triangle that ends badly. But why? What's wrong with just reading a cool story that moves you in some way and allows you to reflect on maybe, um, just one or two ideas? That creates a certain kind of reflective space in your mind that wouldn't otherwise be there, even if you'd learned every detail of 19th century cotton plantations?
That's not to say I condone totally un-researched books, either (at least ones set in this reality). No, go ahead and get yourself to the library, scout around a little, find a nice scattering of details that will give your fiction piece some realistic punch (if that's what you're going for). Go ahead and drive/fly/swim to your fictitious locale and sniff around (see above link). Just don't confuse a bunch of facts with the whole story.