4Fan Fiction Writing Tips
Get to know your fandom.
I think this is the most important part to writing fan fiction. Nobody wants to read a story about their favorite characters acting completely unlike themselves. Also, if you say something never happened that did happen in the movie/show/game/whatever, then it is an AU story (Alternate Universe), or you just don't know what you're talking about. So please, for the sake of everyone involved, if you aren't sure about something, look it up. It's not that hard. It takes Google about .6 seconds to find it in most cases. And you can always check Wikipedia.
Think out your story before you actually write it.
You don't have to outline every single chapter, as I do, but at least know how you want it to end, and have a general idea of how you're going to get there. Otherwise you may write yourself into a corner you can't get out of. Trust me, I've done it, and it's not fun. That's why I outline everything now. And just because you planned something one way doesn't mean it has to stay that way. It's your prerogative to change your mind. Plus if your story is for a TV show, something may happen after you've already started that gives you a new idea.
Be original, or at least add something of your own to it.
Everyone writes a "I was sucked into the show/movie/game/book" story. You don't have to. Don't waste your time on it, unless there's a new twist. I'm guilty of writing a story somewhat like that myself, I'll admit it. It's called "Reality Check." I never said I was perfect, of course I make the same mistakes everyone else does. I've also read a few of the "sucked into the movie" stories. But anyway, if you're going to write something like this, change it up, add a huge plot twist that no one would've seen coming. Make it more interesting than the normal "I'm in the blank and the main character is falling in love with me" or whatever.
Kill Mary Sue.
Not literally of course (I had a teacher once named Mary Sue). A Mary Sue is a character that you write who's pretty much perfect, and of course the main guy in the blank is in love with her. Who wouldn't be? She's perfect. Don't write her. Of course, that doesn't mean you can't create original characters...Which transitions to my next point.
Develop your characters.
To avoid making the terrible mistake of creating a Mary Sue, think about your character. Give him/her a name, age, and all the basics. Think about his/her past, and what made them into the character they are today. Give them preferences, and decide why they prefer those things. Of course you won't use all of these things in your story, but they're helpful when writing this particular character, to get inside their head.
Spell check, spell check, spell check, grammar check...and did I mention spell check?
Some minor errors are acceptable to some people. However, massive amounts of errors will ruin your story, even if it is the greatest thing since sliced bread. Honestly, the only stories I stop reading are those with MANY spelling/grammatical mistakes, too much description, or too many quotes. Nothing else will make me walk away, and not review (unless my computer freezes or something). There are many people out there who share the same views that I do. Anyway, if you want to be respected at all, or have any hope to get anything published, or to graduate high school or college, or get a job, then you should read over your stuff and check all your spelling and such. And yes, I am aware that was a huge run-on sentence.
Get a beta reader, officially or unofficially.
You can't catch all of your mistakes. Really. Since you wrote it, you may read it how you intended it to be, instead of how it actually came out. Plus, they may offer a fresh perspective to your writing.
Take your time.
Don't rush the writing process. Write when you feel like it and when you have ideas. Don't write on deadlines. Unless deadlines help you. Personally, they stress me out and stifle any creativity I might have had before.
Respect, and use, constructive criticism.
If somebody reviewed and said that you're character seems underdeveloped and that you have many spelling errors, go and fix the spelling errors, and if possible, develop your character more. If you're on chapter 20, I'd just say start adding more elements to your characters, with the intention of going back to fix the character(s) when you're finished with the story. Constructive criticism is not to be confused with flames. A flame is a personal attack, whereas constructive criticism is much more specific and not meant to hurt you, but to help you. An example of a flame is:
"You're writing sucks, you're terrible. You shouldn't even waste your time."
That's pointless. Constructive criticism is:
"You need to work on your spelling, you misspell a lot of words. (they may give an example here, or maybe not) And there really isn't much to (character name), they seem one-sided."
Now that's not the nicest thing to read, but it's meant to help you as a writer. Take it as a compliment. People who say that are the nice people, not the people who say, "I love it! Update soon!"
Enjoy yourself.
Write for yourself. Not for other people. Yes, it's a plus to have readers and have them love your story, but just remember you're not doing it for them. Never forget that. If you're getting bored with a story, put it on hiatus for the time being, until you're into it again. Don't ruin a good story by writing it when you don't want to. It won't be your best work.
I hope you found this helpful in some way or another. And just remember, I'm certainly no expert on anything...but that should go without saying.