In the world of science, I tend to focus on writing about wildlife biology & natural history; health & medicine; and engineering & technology -- especially if there's a "green" angle somewhere. I also like to do stories that fall outside these narrow categories; I can only describe the connecting thread as the opportunity to write profiles of interesting people doing cool stuff.
And as you've probably guessed by now, I enjoy doing stories from abroad. I think it helps to get a different perspective.
No matter where the story takes place or what the topic is, I always seek to write about it in a way that makes things clear to lay people like me while still satisfying the experts. My ultimate goal is to be true to the hard science while telling a tale that is engaging, interesting, human, and fun.