What makes readers fall in love with a story? There are many things, but the important one for me is realism. If it doesn't seem like something that could actually happen, I can't get into the story.
I hear all of you asking about fantasy and sci-fi. How can that stuff seem like it could possibly happen? That's where suspension of disbelief comes in. The important thing is to keep your reader from reading a passage and snorting with laughter as he says, "That is so not possible!"
No matter how far out there your plot, world, or characters are, they need to feel realistic even when the main character has three heads and a pet dragon.
Now, I'm going to stick with contemporary and historical fiction, since those are the genres I'm most familiar with. One thing I've run into a lot in my own writing is wondering how to make the setting realistic or give a realistic portrayal of an ethnic group and people in certain occupations. I can't experience everything firsthand. World travel is expensive and to gain the knowledge I'd need of various cultures would be prohibitive time-wise. Plus, if I'm working on an historical, I obviously can't travel back in time.
So here's what I do. I read books, watch documentaries, do a ton of research online. I talk to people who have the knowledge I need. The trick is not getting so bogged down in the research that I start writing non-fiction or, worse, don't write at all. My solution to that is to research when necessary as I write the story. Since I write by the seat of my pants (no planning or outlining before I begin the story), I never really know what information I'm going to need until I come across it as I write. Depending on the story, I may do some preliminary research to give me enough background to write the first scenes believably, but the in-depth research comes later when I need something more specific than the general stuff I've already learned.
Here's an example of what I mean. I've absorbed a ton of information on the military, returning veterans, and post-traumatic stress disorder (PTSD) through news reports, articles, and documentaries. In true writer fashion, my mind started going "What if..." and I had an idea for a story. I started writing with my limited knowledge, asking a few questions here and there, then my story took a turn I hadn't expected. I suddenly needed more than a brief overview of PTSD and what life is like for American soldiers in Iraq. I went online and started utilizing the wonderful search engines out there.
I've spent a lot of time on the Army's website and the Veterans Administration site, as well as reading soldier blogs and blogs of their family members. PBS has been an invaluable resource as well. They've shown a few documentaries about soldiers, including one called "Voodoo's War" that sent cameras with a unit when they deployed to Iraq. The series "Carrier" also helped, even though that's Navy instead of Army. And I can never say enough about how great "Frontline" is.
I know I still have more research to do, and I'll probably find a veteran or two willing to read my story (if I ever get it finished) just to make sure I've accurately portrayed everything. Since PTSD plays a role in the story, I'm also considering finding a psychiatrist with the VA who'd be willing to look over the manuscript. Research is great for a writer, but nothing can compare to the insight of people who actually have experience with what you've written.
I'm sure I'll be rewriting several times, and in fact already know of one spot that needs some rewriting, but the extra effort is worth it for the sake of realism. If I can draw a reader into the story and have him experience everything with my characters no matter how far outside the reader's realm experience it is, I've done my job and made it realistic.
Those of you who write fantasy or science fiction and still achieve the goal of realism, you have my admiration. I couldn't do what you do.
Keep writing and remember to keep it real!