You wrote:

I've been thinking about my plans for my fanfic works-in-progress, and it

led me

to ponder a simple but valid question: How do you plan out a good fanfic?

There is no one right way to do this, but I'll give my way.

My stories usually begin with "The Idea".  The Idea is usually the
beginning of the story, but sometimes it can be the middle or even the end.
 In any case, the beginning of the story is the next thing that comes to
me.  However, I don't consider there to be a story until I know what the
end is.

Okay, now I've got the beginning and the end.  Now, with this in mind, I
map out major points: this happens, then this happens, then this happens. 
With this, I create a road map for a complete story, from the beginning to
the end.  I take one last mental look at the skeletal figure.  Do I like
it?  Is it worth the effort?  If so, the hardest part begins.

I call it "microplotting", and it's the toughest part because it's what you
do while you're writing the story itself.  You break the major scenes into
smaller pieces and connect them with action and dialogue.  It can be
something as trivial as moving a character from one room to another, or
mapping out the dialogue so that main points are hit upon while still
sounding like natural conversation.

You know what's weird?  Sometimes I feel like, at some point, I'm no longer
writing the story.  The story already exists somewhere, and I'm just trying
to figure it out.  Sometimes, I'll be stuck on some point of microplot, how
do I get character from point A to point B.  I'll give up temporarily, and
work on plotting out another part earlier in the story.  When I make a
breakthrough there, the solution to the other problem becomes obvious, as
if that was always what was meant to be.

On the other hand, I have had frustration at times when a cool scene I had
planned from the beginning turns out to have no place in the final story,
like a "booby piece" in a trick jigsaw puzzle.

------RM