Any writing tips you can give.
Whether you're writing a fanfic or something original, the most important thing is to be sincere. Way too many writers fall into the trappings of irony as a means of self-protection which prevents them from being able to express anything of themselves to the audience and results in a story that doesn't truly say anything. If you want to write something good, you first need to believe that what you're saying is worth hearing and if you're not sure, it'll show.
It's always a good idea to show your drafts to people you trust and get their feedback before publishing it. Not only can they point out flaws that you might've missed, they can also suggest ideas that you wouldn't have come up with on your own!
One of my personal rules for writing characters is that a character's greatest strength should also be their greatest weakness. Like, an empathetic character who thinks they always know what's best for others, a strong character who shuts out anything they perceive as "weak," a clever character who's over-reliant on their wits, and so on. I find it makes them feel more three-dimensional!
People don't always do what they think is right but they always do what they think is reasonable. Keep that in mind when trying to come up with conflict.
Don't try to use every single idea you come up with. Sometimes you're gonna come up with something that you really like but which doesn't further the story and while it can be frustrating to let it go, trying to include all your ideas will make your story a bloated mess.
It's okay if not everybody loves the things you make. So long as YOU love them, that's enough!
Above all else, try to approach your writing with a sense of curiosity. Be curious about your story and characters and why things happen the way they do. Be curious about other's work and the things you like about them and why. Be curious about other's perspectives on your work. Curiosity breeds passion and passion breeds great art.