Fanfiction occupies a very weird space for readers. On the one hand, it is often treated with scorn; many people point to such horrendous examples as My Immortal and all of the horrible character romances that make no sense and say that there is no way on earth that Fanfiction can ever be considered literature. On the other hand are those that say it can be and should be; after all, you are paying a great honor to the original creator (maybe) and it's a great way to hone writing skills. Indeed, there are those on the far side of the extreme who love fanfiction and consider it a penultimate form of literature.
For writers, fanfiction also falls into the same dichotomy. For some writers, it is something to be avoided or at least something that they would never do. Fearing the scorn of fellow writers, many would-be fanfiction writers hide in the shadows of Fanfiction.net and never reveal themselves to their more serious literature compatriots. Other writers wont do it all, loathing the idea of working in another universe. And then you get the writers who specialize in fanfiction and roam from failing miserably to doing outstanding works. Unfortunately, the horrendous fanfiction vastly outweighs the wonderful ones and so the treatment of fanfiction continues to be chilly at best.
But fanfiction, like any genre of literature or art, has its benefits if treated well. It is the, if treated
well where most authors fall by the wayside and end up with something that most readers will trash outright and many writers will deride. If you are
serious about writing the kind of fanfiction which readers will enjoy and the original creators of the work would like (if you were to ever meet him or her), then here are steps you should keep in mind.

Fanfiction is not a place where you can just break the rules of the universe willy-nilly. If the original creator of the universe has set down that women never have magic, but they have other things to make them even with the men, for the love of god, dont create the female character who will be able to cast magic and BREAK THE CHAINS OF TYRANNY FOR ALL TIME!!11!!1. There is a reason why those rules are there and you should honor them.

Fanfiction is not a place for you to play God and destroy characters or bring them back to life. If a character died in a universe, leave them that way. If a character didnt die in a universe, leave them that way.

But most of all, and this ties in all the rest of the rules of Fanfiction: Fanfiction is NOT a place for you to lay your fantasies about characters onto the existing canon for all the world to see. Want to daydream about Naruto being gay? Fine, daydream, but dont show us. The laying of your personal fantasies on existing canon characters is what spawns Mary Sues, weird romances, characters acting out of character, and the general destruction of the canon. And therein, lies the contempt because for every one fanfiction reader who loves gay Naruto, there are
three or more screaming bloody murder about it. And you dont want other fans to hate your homage to your favorite author, do you?
Given that so many fanfiction writers wantonly break these rules and create so much disdain for the genre, you are likely wondering why any serious writer should bother ever doing fanfiction. Well, it may surprise you to know first off, that published authors have dabbled in fanfiction. Mercedes Lackey, author of the Valdemar series, the Elemental Masters and a zillion fantasy books besides did; Gregory Keys wrote some amazing Babylon 5 fanfiction (Based on the scripts the original creator did) and there are dozens more besides. So whats the deal? What are the benefits of fanfiction?
Assuming that you are going to do fanfiction correctly-stick with the universe rules, behave yourself with the characters, and leave your personal fantasies at the door- fanfiction has some amazing benefits, especially for new writers, but also for old hats. Just like starting out with drawing by tracing and then using a ton of reference, fanfiction is a foundation stone towards building up your house of amazing literature. But if you want it to be truly effective, you have to put the effort into it or you may not end up learning much at all. Really, if you're going to take the characters someone else has created too far out of context, you might as well skip the middleman and write your own universe.
The benefits of fanfiction are:

Fanfiction teaches
consistency. If you are going to honor your favorite characters, you have to make them right. This is excruciating. Unlike your own fiction where you have to worry about the broad strokes-plot, setting, characters, rules-fanfiction forces you to focus on the tiny details and make them right while still putting your spin on it. This means you have to be consistent. And if you cant be consistent with characters who are already done up for you, how the heck can you expect to be consistent with your own characters?

Fanfiction teaches you detail work. As explained above, rather than focusing on the big picture, youll be focusing on a few dots. This means that you have a wonderful opportunity to really immerse yourself in your favorite characters and the mind of your favorite author. Then when you move onto your own work, you will be hyper aware of the little details of your characters and your universe and your work will be richer for it.

Fanfiction teaches you respect. Theres nothing like spending eight hours sweating over making a character just right to respect the work that went into making that character so wonderful in the first place! It will also teach you to respect other peoples time and effort while you use their universe to tell your story.

Most of all, just like drawing using reference and getting a good piece of work, Fanfiction will give you a boost in confidence before you set yourself adrift in the world of your own fiction. If 90% of people are genuinely in love with your spin on the canon and tell you that you are being consistent, then you know you are doing well in your writing. If you can get the original creators smile of approval, even better-though obviously this isnt always possible.
If you take absolutely NOTHING ELSE away from this, ask yourself this when you are writing your own fanfiction:
Would the original creator like it? Would the original creator say it could be canon?
If you can answer Yes to both of those questions, then youve probably done well.
We're already limited by how much we can change OUR worlds, why should we be limited in our FICTIONAL worlds?
Me? I like to romance characters with original characters because the romances in the media do nothing for me. Why should I go without seeing what I wanted to see when I can hop on my computer and fix the problem? Now, admittedly, I don't write fanfiction, but I roleplay (which is possibly the most hated fan work of all!). I do so with my husband. We shared a few stories with some others and they all seemed to like it, even if it broke all the "rules".
My beef with most fanfiction is not the actual broken rule, but the way in which its broken or the mechanics of the writing itself. I don't like Sally Superlative because she isn't to my taste. I don't want to read about her. But the author clearly wants to be Sally, so let her. In my old age, I've learned to live and let live (you know I did, you know I did, you know I did). I just don't read fanfiction that bothers me or I read it for the laughs it inevitably brings. I don't go and tirade at the poor writer who is just trying to rock her socks.
I mean, fan artists are just as bad. Fan bands sometimes take a canon and throw it in a completely different direction. Every bit of fan work is going to bear the stamp of its author's taste. Trying to labor to please the author, who will never read it, is daft. Just as daft as trying to please some lorehound with nothing better to do than trawl the internet for writing that offends them.
There comes a point where you realize launching polysyllabic critiques is a waste of everyone's time. Just write what you want to write. If it makes you happy, do it.
How about we stop trying to take things, often written by starry-eyed fourteen years olds, seriously?
Always fun to watch.
Personally, when I do fanfic, I work in universes.
Take Star Wars for example.
There is an enormous galaxy out there, with billions upon billions of untold stories. There is so much that can be done without stepping on the toes of George Lucas, and whether it is done as fanfic or as part of a roleplaying game, the freedom is incredible.
Personally, I'd say that's why Star Wars is one of the most fun universes to play/write in.
Similarly, Power Rangers is easy. Just make a new team and exercise your creativity in a recognisable sandbox (in my experience though, it's a heck of a lot easier to do that solo than to get a group together to roleplay it all).
So many potentially-interesting characters just got forgotten by the writers over the years, which is fertile ground for writing fanfic that uses canon characters too.
For the most part, fanfic is about having fun.
Just because there are certain pitfalls to it that are less commonplace in original works (like breaking canon characters for no good reason) it doesn't make it any less valid.
In conclusion, how a fanfic writer treats the universe they're working in will conform to what they want out of the fanfic, and nothing that you or anyone else can say will change that.
Parts of this article were potentially helpful, while other parts were just pointlessly rude... and yet it all did the job of provoking thoughts, so it worked.
Who'd want to read a fanfiction where everything is cannon, just with some minor differences? And did you notice that about 70% of most of the -suitable- fandoms such as Harry Potter are made of fanfiction where the characters become gay anyway?
If I read a fanfiction, I read it to explore what else could have happened in the storyline and what others think of it. When one of my favourite characters dies, why the hell would I read a ff in which the character just dies again and again and again?
Fanfiction writers are artists just like those who draw or make sculptures, take photos or write music.
Would you go to one of the other types and say: 'Hey, if you do a realistic painting, don't include a dragon for gods sake! That's just wrong!' or 'Don't take a photo from this angle, the object will look like it's something else!'
Limiting one's creativity is the exact opposite of what art is about. (For example, all fantasy art would fall under your '
FanfictionArt is NOT a place for you to lay your fantasies about characters onto the existing canon for all the world to see.' category.)Surely there are certain borders where, if you cross them, the outcome will be horrendous in any case (self-inserting, mary sues in general, changing a character -without proper, logical explanation- so much that he/she is not recognizable) but if the authors want to write that way? Let them, the outcome may be technically bad but it still can be entertaining. -See, it's the same with all the other artforms: Don't like, don't look/click/play/listen/watch.
I don't like crossove fanfiction either but is this a reason for me to write an article about how it is an absolute no-no in fanfiction? No.
You make it sound in your article as though the slash fanfiction are one of the major reasons as to why fanfiction isn't treated with enough respect.
I don't know how much/where you read, but in my 5 years of reading everything that comes my way, I've met very few people who are hetero only and even fewer fanfiction communities where slash doesn't outweight the hetero. (In Harry Potter for example, which is one of -if not the biggest fandom right now, there are more Snarry and Drarry fanfiction as all canon hetero pairings put together.)
So please, get your facts straight.
Also, I have NEVER read even ONE hetero lemon which is NOT halfway unrealistic, sometimes downright violent and smutty -where the woman is treated more like a whore even though it's supposed to be first time or at least romantic setting.
In general, I think that the slash fanfiction are better written than the hetero ones, both in pure writing style and creativity. -My opinion though.
Another thing is that you say stuff like 'how are they going to develp their own characters?' -95% of the fanfiction writers are very happy with staying in their fandoms and would never plan on becoming a published author. -Don't project your thoughts/plans/opinions on others.
TL;DR I think your thoughts on fanfiction are very close-minded, eg in the way you write 'should/shouldn't' like your opinion is a matter of fact.
This article basically is about your opinions on fanfiction, not what is indeed there.
To some extent your readers expect a different world, else they would go back to the original work. They want something different from what they saw, and a writer wants to deliver. The key is restraint, and knowing when one is going too far, and when one is tweaking the story/characters just enough to delight.
Some canons call for destruction. The ending could be unsatisfying, and one can't help but think "That could've ended better, and I'm going to write that". Other times, there's an cliffhanger, and one thinks "Okay, where was that going? I'm going to write the ending". Restraint is still key, and the best way to get it is by reading others fanfiction, and getting a feel.
tl;dr Canons need destroyed (to some extent) for a fanfiction to work, but restraint is key.
Sorry for the wall of text.
It doesn't mean "never write anything that didn't explicitly happen in canon". Least of which reason being that there's no point in writing what already explicitly happened, since the original author already wrote it.
Instead, what we tend to really mean is "we prefer people only write what could believably happen in canon/what could have believably happened in canon". Go ahead and write about two characters that could believably gotten together chemistry-wise but just didn't for whatever reason. Go ahead and write side stories that could have happened per the setting's "rules", but the action we saw happened to take place somewhere else. Write missing scenes that were said to have happened but we never saw the details. Etc. etc. Basically, something that didn't actually happen in canon, but could fit (or at least almost fit) as being a canon story.
You could even, by our tastes, write a "what-if story" where the "wrong side" wins, or so-and-so gets together with this person instead of that one. Provided you do it with an eye of logically thinking about how that one difference would happen in the canon, and what would logically result.
And provided you don't fall into the trap of thinking that you even have to make major changes to come up with a good fanfic idea, or that "respecting canon" means you can never write anything exciting or interesting. (I mean, a really good fanfic writer working with a sufficiently "open" universe will be able to come up with plenty of good ideas without going anywhere near the wrong side winning, switching around people's love interests, or similar changes.)
Generally, when we canon enthusiasts start griping, it's because of all the things that are just totally at odds with canon. Characters having personalities that barely resemble their canon ones. Changing canon events willy-nilly just because "you don't like them" with no thought about what effects the changes would actually have in the universe. Changing established fundamental things about a universe (magic in a scifi universe depicted as specifically magic-free, for instance). Writing stories that go against or ignore the whole mood/point/theme of the original story. Pairing up two characters with zero canon chemistry, or worse, completely antagonistic personalities. Etc. That's the sort of thing that drives canon enthusiasts insane, where the fanfic we're reading seems to be a fanfic of <whatever universe> In Name Only.
Also, often times fanfiction is written simply because a writer (and their readers) want two hot guys to make-out. So in this case, the rules of the universe don't matter. The plotand characters matter about as much as they do in pornography.
Understand that, I know what you mean about the rules of the universe, it's just that it cannot be a blanket statement that one cannot break the major rules of the universe ever. Good writers can break any rule they want, any time they want, because that's what makes them good writers.
As a side note, some people simply do not like fanfiction at all, so there is no pleasing them.
Good writers don't have to break rules. Good writers are good writers because of the rules. A great writer can take the rules they're given, and create anything from that base. That is the mark of a great writer. That's why I'm forced in my creative writing classes to write willy-nilly on subjects I detest with rules I abhor. If one can write well a piece on subjects or within rules one does not particularly desire to, think of what one could accomplish with the motivation of working on a piece one does enjoy.
If one feels one has to destroy what already exists to create one's own masterpiece, there are a few undesirables throughout human history I could compare one to.