@Izanasproperty Hello, I apologize for the late reply to your message. I very rarely check my messages here, so I hope you'll forgive me.
To begin with, I'm more than happy to offer writing advice if you require it, however, I don't think I'm the best person to ask. My writing isn't as good as anyone else's, and oftentimes when I go back to my work, I cringe at how bad it really is. But to answer your questions:
1. I basically write whatever I feel like at the time. I get random bouts of inspiration from other pieces of media (books/songs) etc... or what is happening in the manga currently. If you haven't already noticed, omegaverse is my favorite trope to write about. And I do not take fic requests simply because I find it hard to keep on top of my WIPs and the pressure of having to write for someone would drive me insane.
2. In regards to when I upload my stories. Whenever I feel like I'm happy with a finished chapter or a one-shot fic, I immediately upload it. I have ADD so long-multichapter fics are harder to finish, which you'll probably see from my multiple WIPs.
Writing is hard, and it takes time, and you definitely shouldn't rush yourself.
3. Mikey & Takemichi are my OTP!! And Tokyo Revengers has a lot of amazing ships to write about. My favorite character is Takemichi, and at first, I found it interesting to write him with different characters, but I usually come back to Mikey/Takemichi.
I also read a lot of Tokyo Rev fanfics too on AO3, so there are a lot of amazing writers that inspire me too. Once I start writing, I try to finish the piece as quickly as I can, one to get the idea out, and two before I lose interest in it. I easily get bored too. Oneshots are obviously easier to write.
I hope this has helped you in some way. ❤