Some time ago, I read a piece online in which an anonymous writer revealed how her writing career had failed despite her receiving advances that most people would be thrilled with. You can read that piece here.
I've just stumbled upon another piece* that was written by SF writer Charlie Stross in response to it, which explains very nicely where things probably went wrong for her. He does a good job, that Mr Stross.
* Here's a direct link to it, as for some reason the embedded link won't work:
You'll have to copy it across to your browser manually, I'm afraid: I'll fix it properly as soon as I can work out how.