One merit of fanfic that I don’t think gets mentioned enough is that while you are starting off without having to create new characters and worlds, you are also uniquely constrained by the characters and worlds that you choose to write about, because the audience has expectations for them that you must match.
In that sense, it’s essentially a writing challenge in consistency with a specific style, in a particular range of voices that aren’t always your own.
What’s the worst thing a fanfic can be, in my opinion? Out of character. If you’ve come to a fic to read about a specific character, with a distinct personality, style of speech, and set of morals, and the author of the fic hasn’t done their job properly, you won’t feel like you’re actually reading about that character, and you will have a hard time reading the fic.
There is so much that goes into creating a unique character that is easy to not think about until you have the extreme constraint of writing the actions and speech of a character you did not originate, where you have to match the thought process, ideas, and syntax of someone else, essentially trying to insert yourself into the mind of the professional writer who originated the character, and extrapolate how they would make their creation react to the situation you’ve put them in, what words they would put in that person’s mouth, etc.
So fanfic is an excellent exercise in making sure your characters have distinct personalities, and making sure those personalities are consistent. Because if they’re not, your audience will be able to pick up on it immediately.
