Please don't get offended or jump all over me if I don't talk about the method you use on here. I can only speak from experience. I've had more than twenty years of it. (please don't try to figure out how old I am. It will make your head hurt) This is what has worked best for me.
1. You need an idea: Duh. First we need to start with a basic idea. I'll use my own work as an example. After reading Twilight it started me to thinking what if a vampire got a second chance to live his life as a normal person? Could he? I mean, he's obviously been through a lot, seen a lot of horrible things. How could he go back to his family, and would they even accept him?
2. Characters: At this point you need to at least have a grain of understanding who your main characters will be. Some areas of plot will come from your characters. For Vampires Rule my main character is an unhappy boy vampire who longs to go home. Simple enough. I wanted him to have a love interest, so I created Silver. That took a while. At first I wasn't sure if I wanted an innocent girl pulled into his dark world or someone who knows more about the supernatural than he does. I went with the latter.
3. Possible scenes: These will not necessarily all go into your book, but it gives you a good start. By now you probably have at least a few scenes in mind. I know I did. Obviously my vampire would have to go home again, confront family (in his case a brother) who thinks he's dead. I also knew a werewolf would attack him. Then there also has to be a scene where his vampire friends return for him.
Make a long list of possible scenes for your book. Relax. This is the fun part. You can put them on your computer as you're thinking of them, but I like to use a notebook. It's also nice to have someone to bounce ideas off of. For Vampires Rule I had a very interested friend. We talked on the phone about it for three hours that first night. She gave me some good ideas. Other ideas came from something she said that I didn't like, but it led me down a new path. Daydream. Listen to music and let the characters loose in your head, give them permission to breathe.
4. Build a puzzle: I like to think of my story as a puzzle. There are missing pieces at first, but I can fill them in a bit at a time. I look to the characters. How do I want them to meet? (There's a scene). Do they fight, break up, almost kill each other? (More scenes). Part of the plot comes from conflict. What do my characters want? How do they go about getting these things? What's in their way? Do they fail or succeed? You get the picture.
5. Index Cards: I love these things. After I have a ton of scenes, I write each one on an index card. Now comes the frustrating yet rewarding part. You need to put the scenes in order. The thing I love about this system is you can see your story unfold before your eyes. If something isn't working, move a couple cards around. Experiment with it. DON'T forget to number the cards once they are in the order you want them just in case they mixed up. I learned this lesson the hard way.
And that's it. That's how I outline my novel. Please don't ask how many books I've written because I couldn't even guess. I have thrown away more manuscripts over the years than I can possibly remember. Anyway, I hope this is a helpful article to you. Happy writing.