elementrolls asked you: I'm one of those people who tends to have a lot of ideas from the get go, but I have a hard time deciding what's just a fun idea (that I might explore in a sequel or another book) and what really needs to go in the story. Any tips on focusing?
One of the pseudo-problems I run into when brainstorming happens when I get a bunch of ideas and suddenly I think I have to either pick this idea or that idea, when most of the time, I can use both ideas. So if you have a lot of ideas, try to see if you can use most of them.
With that said, there is a point where you have to stop yourself or your story will get longer than Lord of the Rings, which isn't a bad thing, but most writers aren't looking to write stories that long.
There are also times when you don't want to use all of your ideas; for example, if you are writing a medieval fantasy, you might not want to throw in time-traveling aliens after you already have a quest story for the main plot. Time-traveling aliens just doesn't fit.
For sequels, a good technique is to look at how you can broaden or deepen your storyline so that the conflict goes farther or deeper than the book before.
So if in book one, a town is threatened by a villain, in book two, make the whole country threatened by a villain, in book three make the whole world threatened. To make it deeper, you look for ways to make the conflict in book two more personal than the conflict in book one. Say you are writing a sequel to a detective book. Perhaps in book one, the detective had to solve a case for a citizen. In book two, he has to solve a case for his own daughter. You can broaden and deepen a storyline at the same time: in book two, the detective has to solve a case that involves multiple cities AND his daughter's life.
Another technique is to make the villain who was defeated in book one turn out to be a pawn of an even larger villain the heroes didn't know about.
Some series are simply episodic. The sequel doesn't need to be better, just as good as the first book, but different than it. Most t.v. shows are like this. Each episode is its own little story. We might have our favorite episodes, but it's just preference.
To help with focusing, I would just say pick one conflict to be the main conflict, another to be secondary, and another to be tertiary. What belongs in the story also depends on what kind of story you are writing. Check out this podcast on the M.I.C.E. Quotient and it might help you figure that out: http://www.writingexcuses.com/2011/08/07/writing-excuses-6-10-scott-cards-m-i-c-e-quotient/
Hope that helps! Good luck!
Next week I hope to have my post about writing in third-person up, but I have a couple of posts after that to go with it. They were all in one post, but I realized they might need to be broken up, and contrary to popular belief, some of the subtopics of third-person actually relate to first-person and beyond, so they will be their own post now.