Writers write about what they know, or so the saying goes. Of course, the joy of writing fiction is that it's all make-believe, so I don't have to know too much. Just a little bit of knowledge goes a long way (and can make one rather dangerous, but I digress.) More than book-smarts, to me, is real-world experience; that is, literally experiencing something directly.
Now, I don't recommend that mystery and crime authors take up serial killing or dying just to get their arms around the experience. (See above about writing fiction and make-believe.) Elmo sings a song about using one's imagination, and it holds true for adults as well as children: you can go anywhere and do anything in your imagination. So imagine big. But it's important to ground your imagination in reality. Readers will be willing to suspend disbelief, but only for so long. You have to meet them halfway. Tell them the sky is pink, but do so by showing it clearly through your words.
What I'm finding as I do more writing is that as I experience something particularly painful, I have a tendency to file away the feeling even as I'm experiencing it.
Case in point: I was stung by a bee when I was 21. I was ambling around the house barefoot, not really looking down at the carpet to see if there was, you know, shards of glass or dog poop or dying bees loitering around. Sure enough, I stepped on said dying bee. Holy crap, did that hurt. I'd never experienced such sharp, unforgiving pain before. (This was way, way before I went through the joys of back labor.) I remember sitting on the floor, clasping my foot, tears streaming down my face...and thinking about how much it hurt, and what it felt like, and how I needed to remember the feeling. Seriously. (As for back labor, within two weeks of giving birth the first time, I had blissfully forgotten the extreme agony that nearly caused me to break Loving Husband's hand as I held it in a death-grip. I think this is God's way of ensuring that mothers agree to have more than one child.)
Another example. Yesterday, Loving Husband, the Tax Deductions and I took a road trip to visit my grandmother. One of the things that really sucks about seeing your loved ones old, fragile, ready to break, is that you may recall vividly how strong they were when they (and you) were younger. My grandmother was an imposing force of a woman. The unquestioned matriarch on that side of the family, she was unapologetic as her opinions became law, no matter how others may have objected. I love my grandmother dearly. To me, she will always be an unstoppable power who pinches pennies and dictates how things should be done. So it is especially jarring to compare that image, firmly locked in my mind, to that of the woman she is now: 89, unable to walk or be self-sufficient, shrunken in her wheelchair. Grandma doesn't really talk anymore, but she did wind up throwing a koosh-type ball with Tax Deduction the Elder for a few minutes. And the joy on her face was breathtaking. My son performed a mitzvah yesterday, and I'm proud of him for giving my grandmother such pleasure. On the long ride home, I tried to understand my feelings--not just the emotional maelstrom, but the physical sensation of contemplating age and, ultimately, death. I felt a tingling, heavy sensation in my shoulders, back and chest, and I realized that I was feeling my heart hurt for my Grandmother Who Was.
I've heard it said that we remember pain and discomfort far easier than joy and happiness. In my case, I think that I actively try to remember the bad to get a handle on those emotions when I write about my characters. As for joy and happiness, well, those are easy to remember. All I have to do is look at my Tax Deductions playing (and not beating each other up for the moment), or at Loving Husband, who says this about our family, no matter what: "It's all good."
And it is--even the painful parts.