One of the most common pieces of advice for writers (that I've heard, anyway) is "Write What You Know." But, what does that mean?
I know that 6x4=24. I also know the sky is blue. And if I didn't know these things, I could easily learn them.
So is that what it means to write what I know? I'm not so sure. I think it means something deeper: Write What You Know In Your Heart.
But what does that mean? Simply put, it's what you know that can only be learned through experience. For example, my parents divorced when I was three, and neither remarried. So I know what it's like to be raised by a single mom. Conversely, I don't know what it's like to be raised by a two-parent family. I can do research on this and make an educated guess, but I'll never truly know because I didn't experience it growing up.
Another example. When I first learned I was going to have a baby, I was thrilled. I love kids, and spent my high school years babysitting. I thought I knew what I was getting into, but I still did lots of research so I'd be well prepared. After my son was born, I learned that no amount of research could have prepared me for this experience. It's baffling, frustrating, and rewarding - all at the same time. I had no idea how much it would change me and my view of the world. And I wouldn't give it up for anything. But it's something I had to experience in order to really know.
I think that we, as writers, can take our experiences, expand them with research, and then put them on the page. I also think it works the other way - expand the research with experiences. In either case, I think it will give us something truly amazing.