Last week, I talked about my personal, and to some degree irrational, bias against fan fiction. I don't like having irrational biases, so I've worked on finding positive uses for fan fiction. I've concluded that beginning writers may want to start writing fan fiction, on the condition that these writers are serious about improving their fiction skills. I can also say I don't remember ever hearing or reading any writing instructor suggest using fan fiction in the way I'm about to, so as far as I can tell, my advice here is original.
A beginning writer attempting a complex story--especially a story set in any world that is not pretty much the same one the reader lives in--has a lot of work to do. The world has to be introduced, characters have to be introduced, some kind of problem has to be introduced... it's a lot to grasp for someone just starting out.
Fan fiction does a lot of the work for you. Let's say you're going to write a fanfic episode of the now-finished TV show Eureka from the Sci-Fi channel. (Oops, I mean "SyFy" channel--don't get me started.) Your setting is pre-made: a town full of genius scientists, most of whom are weird in some way. Your characters are set and you've got a broad range to choose from. Your plot is half-set; virtually every Eureka episode is about Sheriff Carter and his allies trying to solve a mystery caused by one or more crazy experiments that have gone wrong. And best of all, since fan fiction is written by and for fans of an existing fictional world, all your readers will already know this world, these characters, and this kind of plot. So look at all the work you will not have to do! You don't even have to describe what these people look like, if you don't want to. Your readers already know. All you have to focus on is your story, which is the fun part.
If you take this exercise seriously, and show your fanfic to cooperative fans of the show, then readers will complain if your version of the show's characters don't act right. If you get basic facts wrong, you'd better be clear you're writing some kind of alternative version of the show or you'll get negative reactions, too.
Fan fiction, when taken seriously, forces writers to think about their characters and the story's world. You have to constantly ask questions like, "How would Sheriff Carter react if...", and "Does that really sound like a line of dialogue Jo Lupo would say, especially that early in the morning?"
Fan fiction can be a great exercise for writers who struggle with worldbuilding, character development, getting different characters' dialogue to sound different, and tone. And probably some other things.
On the other hand, it won't help with pacing, an area where most fan fiction is especially dreadful. The fanfic I've forced my way through generally wastes page after page describing events and scenes of no importance to the story. If you're on page 20 of your Eureka story and nothing strange has happened yet, you're doing it wrong.
Next week, I'll tell you how I think fan fiction can help you improve your pacing. But for now, have fun with this link, in which Kate Lawrence pokes fun at some of the worst excesses of fan fiction's fringes. (You'll need to scroll down a bit; there are ads at top.) Articles like hers make me feel my irrational dislike of fan fiction might not be quite so irrational after all.