Some people can spin out a story ending whenever needed, without any apparent trouble at all. These lucky people can just start wherever they like, write their story until they hit the end, tie off a few knots, cauterize a few bleeding wounds, and call it good. I figure if you’re one of those people, you’re not reading this; so I’m perfectly safe going back into denial about their existence. So, once again, bear with me while I preach, and I hope that anything I say is helpful.
As far as I’m concerned, the key to a successful ending is having some notion where you’re going before you ever get there. Since I’m writing this in the air, you get a bad, flight-oriented analogy: it’s a lot easier to touch the plane down with at least 50% of the passengers (nobody’s perfect, after all) still breathing if you know which runway you’re aiming for.
You should always do some preplanning before you start your rough draft. This doesn’t have to be like those papers you wrote in elementary school you don’t have to outline every little paragraph and stick to it. However, there are a few things that you should have pre-planned.
Okay, you ought to preplan a good number of your characters. Figure out who they are, figure out where they came from, and then take them out to tea. Next, give them something distracting, and figure out ways to make their lives utterly miserable. Or, you could decide not to… either way, you should make sure that your plot and your characters go together well. You can always figure out what you want to do with your story first, and then get characters who fit that story well, but I generally start with characters and then the story develops around them.
I understand that you’re going to want to have at least a little of your story dependent on chance and what you feel like writing while you’re writing. That makes perfect sense, and I always let the flow while I’m writing determine the details of each chapters. Personally, however, I do a little more pre-planning than most. This is primarily because of the exceptionally slow pace that I write at by the time I get to the next part of the story, I’ll have had so much time to plan it that I generally know what order I would like the scenes to go in. This isn’t a hard and fast outline for me; I deviate from the plan when it improves the story. However, the important part is that I know where I need to be at the end of the chapter, and ultimately the end of the story.
At the bare minimum, you should know where the story begins, have some notion of what is going to happen in the middle, and figure out where it’s supposed to end. Knowing where the characters need to be by the end of the story can help you to pace it well, so that your ending doesn’t seem too sudden or if you want a sudden ending, it can help you set things up.
So. You know where the story needs to end, but what kind of an ending are you going to put on it? There are several different types of endings… for instance, do you want your story to be surprising, or do you want it to have a well worked out, slower sort of ending. The reason it’s important to know ahead of time is that if you do decide to make a surprise ending, you’ll have an easier time of it and the ending will be better than it would be ordinarily.
Bad surprise endings come out of left field with no build up or explanation. These are the sorts of endings where Johnny gets to the end of the story and tacks on “And then Joe woke up and it was all a dream!” or “And then SPACE ALIENS came down and ATE JOE.”
In order to write a good surprise ending, you need to have a little bit of build up earlier in the story. This doesn’t mean that you need to make it obvious, or that you need to give everything away before you get to the end, but you should give us a few hints as to what’s going on. For instance, the surprise ending in M. Night Shymalan’s The Sixth Sense worked because you would realize that it makes sense after recollecting the details of the film.
This is where the details come in. If your character is going to, say, be revealed as a vampire at the end of the story, and in your story, vampires can’t be seen in mirrors, then you should make sure that you never show your character with a mirror reflection. These little details make the ending better, and on a larger scale, they’re one big reason why even surprise endings require pre-planning.
Also, you should make sure that either your surprise will finish wrapping up all of the important questions in the story, or that they are questions that ought to be left unanswered. If it’s better for your story that the reader isn’t quite sure what all has happened at the end, then you should figure out which story threads you should leave un-tied.
Unfortunately, there’s really no one way to figure out exactly how much you need to wrap up at the end of the story. Like every other part of writing, it’s going to take lots and lots of practice which is one reason why you should try writing some short stories before you move onto your Great Amazingly Long Novel. The more endings you write, the better you’ll get at them and by tormenting your readers into giving opinions, you can figure out if your endings are getting the desired effect.