So, I think we've all been told at least once or twice to write what we know. It's comforting. We understand what we're writing, we're less likely to make mistakes, and its a familiar world in which we can mold to our desires.
Well, that's great for brand new writers who don't know the ropes. But if you've written a couple of novels and have ben around the block a few times, you may want to step out of that box.
Think about it this way, if everyone wrote what they knew, it would be a lot of contemporary with very little plot-driven novels. Agents aren't looking for the same thing. They aren't looking for the million contemporary novels about housewives in middle-america. They want new and interesting stories. They want something they haven't read a million times before.
So pick a topic that interests you, something you don't know that much about and find a story there. If you're a romance writer, you may look into the Spanish inquisition period or the 30's and find a love story in the past. If you write historical, head to Russia or New Zealand. Yeah, there's going to be a lot of research, but all that hard work just might put you over the edge and get you in print.
You can tell I'm still recovering from the flu with this wimpy blog post. Oh well, that's all I got in me. Be original! Be brave!