If there's one trait that separates the good writers from the bad, it's a streak of utter ruthlessness. For a good writer, there is one goal and one goal only: To make money. Okay, two goals: To make money and to produce the best piece of writing possible. To that end, a writer must be willing to make the ultimate sacrifice. He must be willing to kill his babies.
I don't mean literal infanticide, though that's probably easier for a writer to handle. I mean being willing to let go of an idea, scene, character, joke, plot device, title or anything else that doesn't make the novel, screenplay or whatever better. No matter how much you love it, if that line of dialogue or that simile doesn't make that comedy funnier or that drama more dramatic, then it should be deleted without a second thought.
It's not easy. Believe me, I know from experience. I've fought pitched battles to keep jokes in scripts only to admit at the read-through that they stank. I've insisted that the play be called "hedgehog curry" until the fliers went to the printers before conceding that no one else understands what it means. I haven't seen my novel about an academic who survived the Stalinist purges and is now having flashbacks to that time; his daughter whose long bitter marriage is falling apart around her and the journalist who's investigating the academic because he suspects he was never in Russia at the time and then he falls obsessively in love with the daughter and sacrifices his career to become a lense grinder in Omsk turned into a story about an elephant who loses his balloon, but I've come close. I've had to kill a lot of babies in my time
I have a friend who is a very good and very successful writer down in Hollywood who not only can't kill his babies, he can't even move them into the next room. He's one of those writers who needs a crutch to get started; a plot device on which to hang the rest of the story. It might be that the hero is seeking a long lost relative or that there's a bomb planted on a train. It's a tool that works and he would very often come up with some superb plots, but he would invariably fall in love with his crutch and refuse to part with it. By the time he'd finished writing, the story had altered so much that the lost relative or the bomb had no bearing on the plot at all, but he still kept it in despite it morphing from a writing aid into a pointless subplot that brought the story grinding to a halt. The result is that many of his stories aren't as strong as they could be and he ends up making a lot more work for himself in preserving what should be cut.
My personal example of the need to kill babies was a play about the abolition of the English monasteries that I submitted to a competition a few years ago. It was one of the winners and ended up in production, but when I saw it up on stage I had to admit to myself that what I'd thought of as a tight, focused personal drama was a one-act experiment in tedium that lumbered and dragged itself across the stage from one unending speech to the next. So, I dusted my script off and hacked away at it like a crazed gardener faced with an overgrown bramble bush. I went after every line that I thought couldn't possibly be altered, every character who couldn't possibly be cut, and every plot point that I thought indispensable and I altered, cut, and dispensed without mercy. In the end, my 45 minute suet pudding became a lean ten-minute play.
This sort of thing happens more often than most people realise. Take the classic film Dr. Strangelove or How I Learned to Stop Worrying and Love the Bomb. When Stanley Kubrick started working on the film, it was a serious Cold War drama that never had a breath of humour to it. But as the work progressed, Kubrick and his writers cracked so many jokes and ended up laughing so much that they realised that the story worked much better as a black comedy than as a drama. So, out went the solemnity and in came General Jack D. Ripper's precious bodily fluids. The same thing happened with Monty Python's Dead Parrot sketch, which was originally about a second-hand car until Graham Chapman and John Cleese crossed out "car" and wrote in "parrot". I think that's one of the main reasons why Monty Python was always funnier than Saturday Night Live in its heyday. The Python lads never gave a toss how much someone liked a sketch or the fact that so and so didn't have enough lines that week. If it didn't make the show funnier, it was out and that was the last word.
The moral of the story is, if what you're writing isn't working and you can't fix it, then you're too kindhearted. Take out the blue pencil, close your eyes, and start crossing out. It's hard at first, but after a while you'll find that you can edit your work with all the dispassion of a surgeon. Or a butcher. Whatever gets the job done.