Re: Write what you know
My own feeling is that you shouldn't write what you are likely to be caught out not knowing, which isn't quite the same thing as only writing what you know. Many people have been divorced: I haven't, and although I have a rough idea of what's involved, it's from the outside, and hence I would be wary of writing about characters experiencing a divorce from the inside. On the other hand, very few people have actually been in a gunfight, and, having read several very convincing accounts of gunfights (real and otherwise), I think I would be able to write one that would seem convincing to all but a few experts. Quite often, I suspect, it's the emotional elements of a novel that feel fake more than the physical ones.