Sixth, bullying other writers or judges during contests, harassment and bribery. Why can't we all have some clean fun and support one another instead of trampling on others?
Seventh, super looooong "Author's Note" at every chapter. Just tell your readers you will be on hiatus because of personal and health issues. I'm sure they get the memo
Eighth, the huge spaces. Is this suppose to be a page break or give your readers an existential crisis as they stare into the void of space? They're often used between paragraphs and at the end of the chapter. At least double spaces is enough if you want to indicate a shift in setting or time frame.
As for number 9, the glorification of toxic relationships, violence and other "No-No" content.
It's quite ironic that they'd still be up on the platform while the ones who neither have any of these stuff get taken down, considering how inappropriate stories are said to break community guidelines. What is quite concerning is they're mostly written by young teens.
Lastly, asking personal questions in the DMs (age, location, background, race). It's best for the other person to disclose a few deets on their own accord. The Internet is a double-edged sword. Whatever you put out there can be used against you.