I've used different methods of coming up with ideas over the years. When I used to write every day, and had lots of story ideas, most of my ideas came from my dreams. I'd wake up and wonder, "What happened to that guy/girl/dog who chased me through the corn field/pushed me down the stairs/joined me in the shower?" So I'd write what I remembered of the dream then just write whatever came to me. I was just writing the story so I could learn what happened. I enjoyed this method as it was fun for me to learn the story as I went along. However, it wasn't very organized. Sometimes I'd end up with an entire notebook full of words, but it didn't have a plot or any real point. However, I learned more about my characters and if I really wanted to, I could consider those stories prewriting now and pick the kernels from the chaff and outline it into novels. I started Alaskan Healing for a class I was taking online with the wonderful Loree Lough in 2006. It was the night before the class started and I was supposed to have an idea to work with. I'd procrastinated and procrastinated some more, thinking, "Damn. I hope an idea shows up otherwise this class is going to be a waste of money."
Grumbling about my muse's refusal to cooperate, I sat my butt on the couch to watch tv with my husband, he flipped the channel to Deadliest Catch and I said to myself, "I wonder why there aren't any women on any of the boats."
Aha! I had my idea. Thank you, Ms. Muse.
I wrote the rough draft of the hockey novel I am currently revising (no title so far) during National Novel Writing Month in 2006. I followed part of the Snowflake Novel Writing Method, but the initial idea came from watching too much hockey. (Blasphemy! There is no such thing as too much hockey!)
In August (2012), when I finally started working on Alaskan Hope (the next Alaskan Healing novel), I wasn't sure what I wanted to write. I had a good idea who my characters were going to be, but not what they were going to do. I used Freemind mind mapping software to get a bunch of ideas on paper/screen and sorted through those ideas to find the main "what happens to them" of the story.
There have been other various ideas between the hockey novel and Alaskan Hope, but I don't know that they'll ever amount to anything, so I didn't mention them in this post.