Choose Your Audience: Canon or Non-canon

Canon stories strive to keep the characters true to themselves, and their reactions true to their characters. They may add character development, or expand on the interpersonal relationships (romantic and not) apparent in the original, but they do not try to alter them. They do not play mix 'n' match with the characters' love lives. In contrast, non-canon fics work on the principle that fanfic doesn't need to mirror the original work. Virtually anything goes: the writer may introduce drastic personality changes, alternate realities, new abilities, new love interests, and anything else that strikes his or her fancy.

Fanfic readers and writers disagree - often vehemently - as to which type of fanfic is more appropriate, and which has greater merit. As such, it's important to understand that every fanfic you write will fall into one of these two categories, and that the reception your work will receive will vary depending on who the target audience is. Generally, I think that the non-canon authors receive more negative feedback, as canon readers tend to be more outspoken about their likes and dislikes... and what they like are canon stories. Regardless, whichever you choose you're going to receive criticism from the opposing camp. Rather than try to please everyone, write whatever satisfies you as the writer... but make sure that when the time comes to share your story your expectations are reasonable.

Do your Research:

It's always best to have your facts straight, particularly with respect to things that actually happened in the original anime or manga. However, researching other aspects of your writing can be helpful as well. When choreographing a fight to take place indoors, perhaps it would be useful to know something about Japanese architecture. When creating a villain, perhaps knowing more about Japanese martial arts would help make him more believable. Instead of just "making something up", you'll probably find that a little research will provide you all the information you need... and that the "real" depiction goes over better with your readers than you're fictional explanation would have.

That said, the best search tool I've found on the internet is MetaFetcher. It accesses search engines I've never heard of before, and - surprisingly - I've had better luck with some of those oddball engines than with the big names.

Crossovers, Adaptations and Parodies

These three terms are used interchangeably on the internet, but actually refer to three distinctly different types of story. A crossover takes characters from two or more fictional worlds and involves them in the same plot line; an adaptation retells one story using characters and situations from another; and a parody is essentially an adaptation written with the intent to mock the original. So -- for example -- if you write a version of the Princess Bride using Sailor Moon characters, you are writing an adaptation - possibly a parody - not a crossover.

When writing any one of the three, be aware that your audience may not be familiar with all of the fictional worlds you are blending. Adaptations and parodies are most enjoyable when the reader knows something about the original. Crossovers become confusing and the reader disinterested when more than two series are merged. Try to use well-known stories for your adaptations or parodies, and keep the crossover characters to a minimum - feature one or two favorites instead of the entire cast.

Spelling and Word Choice:

It's impossible to over-emphasize the importance of using a spell-checker. There's absolutely no excuse for not using one. Do it. Yes, there are people out there who won't notice the difference, but those of us who do notice will thank you for it. If your word-processor has a thesaurus, you'll find that a handy tool, too. Varying the words you use will make your writing more interesting to read. Do not, however, use words or idiomatic expressions with which you are not completely familiar. If you only think you know what something means, then take the time to look it up before you use it. Nothing ruins the mood of a scene faster than a misused word or idiom... which reminds me: your characters wear clothes and polish the floor with cloths. They lose at poker and sometimes their clothes may be loose. If someone is tired they may be described as weary, and if a character seems suspicious, then the hero is probably wary. Fanfic writers are constantly - constantly - confusing these. It's particularly amazing the number of anime heros who frequently have to change their cloths, or have trouble holding on to them.

Proofreading:

I find it best to wait a few days before I try to proofread my own work, because when the story is fresh in my mind I have a tendency to read what I think I wrote - what I intended to write - instead of what I actually did. This is why it's helpful to have someone proofread for you: he or she is unaware of anything beyond what's on the screen or printed page. However you decide to go about it, proofreading your completed story is just as important as spell-checking it.