There are people in the world who hate outlining. They say it takes the creativity and spontaneity out of writing. I used to be one of them; I'm not any more. Outlining doesn't have to be a heavy, in-depth, page by page map of your story. It can be, if that's your thing; it could also be, say, a few notes jotted down on the back of your napkin. Heck, it can be a mental outline, if you really hate the thought of writing it down.
Here's why you should have some sort of outline, though: it helps you organize your thoughts. If you've got an outline and you're stuck, you can check it to see what the next thing that has to happen in your story is; without one, if you're stuck, you end up floundering. You may come up with something great, you may not. You avoid that problem entirely simply by having an outline.
The very basics you should ask yourself in an outline are:
Who's the protagonist? Or who are the several protagonists? These are the main characters, the people the story centers around. You can have a main cast of two or three and then a lot of people in the background, but you'll want to focus on the two or three who are the most important.
What is the protagonist's goal? In other words, what does your main goodguy want out of the story?
Who or what is the antagonist? Or, again, the several antagonists? These are the badguys, though it doesn't have to be a personmaybe the harsh winter of 1900 is kicking your poor protagonist's ass and he has to find somewhere to get warm. The antagonistic elements are the things that are in the way of his achieving his goal. Without these, there's no story.
Does the protagonist achieve his goal? He doesn't have to, you know. It's usually more satisfying if he doesin other words, if he winsbut not really necessary. He should get something out of the story, or learn something, or in some way grow, but it doesn't have to be what it wants.
How does he achieve his goal? Or why doesn't he? This is, essentially, the basic action of your story. Goodguy wants something. Badguy stops him from getting it. This step is how the goodguy overcomes the badguyor doesn't.
As always, to use my own stuff as an example, in Better Than Nothing:
* Mush is the protagonist. The biggest supporting characters are Racetrack and Blink.
* Mush's goal is to be with Blink, romantically. (Yes, it's slash; bear with me.)
* The antagonist is actually Blink, or at least the fact that Blink is straight.
* The protagonist doesn't achieve his goal. At the end of the story, Mush still has a thing for Blink; Blink is still straight (and clueless).
* He doesn't achieve his goal because he can't change Blink and isn't willing to talk to him about it. However, he does growhe comes to accept that it's good enough to be best friends with Blink. He does it by talking with Racetrack.
That's all you need for a basic outline, but for a slightly more lengthy one, once you've got those questions answered (and they can be quite hard to answerespecially the "how" question) you might write it out like this:
Introduction This is where you set things up. You introduce your protagonist and hint that the antagonist exists. You show the status quo and explain or hint about how the status quo is about to be shaken up.
Establishing Event Something happens that destroys the status quo and introduces the plot. This should be some sort of meeting between the protagonist and antagonist.
Rising Action Things build up. This can consist of as many events as you choose, probably more meetings between the protagonist and antagonist. Things in this section build and build, until they're about to burst.
Climax This is where things do burst, the final confrontation between goodguy and badguy. One of them wins, or maybe they both get what they want. That's up to you.
Conclusion In here, things get mopped up. Any remaining questions are answered and stray plot points are concluded. You may want to show characters having returned to the status quo, or having established a new one, since they've probably matured a bit.
Let's us another example for this, but for a change, not one of mine. (Gasp!) Let's look at a very basic outline of the movie itself.
* Introduction AKA, the Carrying the Banner sequence and a bit after it. In here, we meet Jack and he's set up as a leader, someone good in a fight, and the best newsie in Manhattan. That's the status quo. Next, David is introduced; he's set up as smart, nice, and pretty innocent. Also included in the introduction (the post-CTB bit) is our first meeting with Pulitzer and his cronies, plotting to do something to make more money. Nothing is really explained, but it's ominous.
* Establishing Event The guys hang out for awhile. Pulitzer decides to jack up the price. The newsies go to get their papers and are royally pissed. With Jack and David in the lead, the strike is on. Gauntlets are thrown. And the audience is intriguedhow will a scrappy band of newsboys possibly be able to stand up to a bigshot like Pulitzer?
* Rising Action There's quite a lot of this. They meet with Spot and a few scenes later, Brooklyn joins the fight. There are a few riots. Jack is arrested. Jack becomes a scab. Jack stops being a scab. Denton walks out on them. Crutchy is thrown in the refuge. Everything is building up tension for a final confrontation.
* Climax AKA, the Once and For All sequence, and events directly following it. The reenlist Denton's help and have a crazy plan to put out their own paper. They do so, and there's a huge rally. Jack and David go up to Pulitzer's office and confront him.
* Conclusion The win! Huzzah! The crowd cheers, Jack goes off, the guys return basically to normal. They sing the introduction to CTB again, they're so normal. But then you see how they've changedJack comes home, since he's realized what he needs is his good friends in NY. David has learned some street smarts, illustrated through his Hat Adjusting Action ™. The romantic subplot between Jack and Sarah is tied up. Everything is happy. They sing the end of CTB and dance a bit, and the credits roll.
See? It all fits. That's the basic story format. You should have some idea what your beginning, middle and ending are, so that you won't get stuck on your way there. Stories can grow and change and matureyou may end up with nothing even vaguely resembling your outlinebut you'll want to have something to work from to avoid getting lost in the middle.