Last Saturday's Guardian Weekend had an interesting article on the writing habits of Anthony Trollope, one of England's most successful authors. He wrote dozens of novels while still holding a day job for much of his life and enjoys good sales a century after his death. Yet he only wrote three hours a day.
His philosophy was that "three hours a day will produce as much as a man ought to write." He didn't worry how much he was writing, or even if the prose sang from the page, he simply put in his three hours and went off to his day job. Interestingly, if he finished a story or novel and he still had some time left on his writing shift, he started the next one. No histrionics, no drunken benders to get the creative juices flowing, no stress, just his ass in a chair for the set amount of time every day. That's how he established one of his country's most enduring literary reputations.