So I write fanfiction.
This used to be something I would just tell a few people, people that I could trust not to tell anyone else, because it is such a stigmatized activity. Like, how could I do something so very far from "real" writing?
Only that couldn't be further from the truth.
When I started writing Teen Titans fanfiction when I was just barely old enough to even be part of online forums, I connected with a wonderful woman, who was a college student at the time, who for some reason took me under her wing and decided to mold me, to teach me about writing and to help me improve mine. The editing and polishing tricks I was taught in editing courses in college were already tricks I was actively practicing
In my most recent projects, I've been able to stretch the boundaries of what I usually do. I've experimented with nonlinear storytelling, with shorter, more staccato and off-the-cuff styles of narration, and with limited-knowledge points of view.
I've learned how to react to fan mail and requests (okay, so I'm still learning how to respond to people saying "oh I really like your writing but I wish you would do this" like, okay, I'm not a jukebox), but other than my knee-jerk fear of people telling me what to do, I think I've been largely successful.
I've built up a nice repartee with a few very kind individuals who always take the time to review and who have even taken time to build a personal connection, who aren't afraid to ask in-depth questions about the background of the universes I've built that likely won't even appear in the story itself just because they're curious.
And I've been able to see my writing improve vastly. Lady Thief was basically finished when I was sixteen and hasn't changed much since then. It's my writing from seven years ago! And Birthright Unknown, while I did a rewrite in college, is still largely the same book it was when I finished it at eighteen/nineteen including the rewrite. That's four years old!
So the best feedback I'm getting, for what I'm doing right now and how I can improve my writing right now is fanfiction. I'm learning how to slow down and not take my writing at full speed ahead. I'm learning how to let relationships breathe and how to differentiate character's voices.
So now, when I tell people I write fanfiction, I also mention that it's beautiful practice for all aspects of writing, that it's a wonderful way to use creative energy when you have writing block for other projects, and that it's the best learning tool there is.