Step 3: The research
Before we start writing our fanfic, we first have to research the characters and worlds that we are gonna write about. And what better way to research them than to read the source material! And by the source material, I mean the anime. Well, we could also read the manga or light novel from which the anime was adapted, but we won't for two simple reasons. 1) Because they are too long and 2) because we would have to actively read the manga or light novel and would have to use our brains to process all the information instead of passively watching anime. Basically, we are just too lazy to actually READ something. Don't worry, you won't miss anything by just watching the anime. Animes, especially light novel adaptions, are known for their faithful adaptions and how they never cut any content that contains important plot points, characterization, backstories, or worldbuilding. If you ever hear that an anime studio squeezed 50+ manga chapters or 5 light novel volumes with 200+ pages each into a 12 episode long anime then don't worry, that just proves that the jump from written to a visual medium is super easy! But what do we do if we have to write about animes like one piece that have 800+ episodes or if you are so lazy that you can't be even bothered to watch a 12 episode long anime? The answer to that is simple! Don't even watch the anime and instead get all the information about the series from the fanfic you once read. It's that easy! You don't even need to go to the fan wiki to check if those "facts" are even true. I mean, why would the horny and edgy teenagers who write those fanfics ever twist the facts or make stuff up? Trust me, reading some random fanfic on the internet is just as good as watching the show. Well, there may be some fans( short for FANATICS) who will be able to tell that you didn't even watch a single episode and will tell you that your fanfic is unfaithful to the source material, but what do they know? They once wanted to convince me that there is no such thing as a Clan Restoration Act in the Naruto manga. What's next? All Might is not Dekus's biological father? Luffy never ate the Goro Goro no Mi? Do you want to tell me that Rias is not an evil manipulative bitch and is in fact one of the nicest characters in Highschool DXD? I mean really, how ridiculous can people get?
Step 4: The characters
Now that we finished all the preparation for our story we can finally move on to actually writing it. We will start with the most important process of writing and that is creating your characters. Without characters, there can't be a story and that's why we will start with creating the story's most important character, the protagonist. But what kind of protagonist should we put into our story? Of course the laziest one, the SI (self-insert) protagonist. Actually, a self-insert protagonist isn't a bad choice at all, after all, there is no person in this world who you know better than yourself, right? However, your self-insert protagonist will not actually be an exact copy of yourself but an idealized version of yourself. You see, we don't want people to see our flaws and weaknesses and that's why we will remove them or present them as strengths. Be sure to present all of the MC atrocities like stealing another man's wife or killing someone as a noble thing because he is strong, "smart"(?), "badass" and...you. Be sure to make the protagonist as cool, manly, and perfect as possible so the audience will like him(you). Remember to give him a sad past so he can get pity points from the audience, even though that sad past will never affect him in the story in any meaningful way. Do you want to make a clear distinction between good and evil? No problem! Everyone who agrees with your protagonist or is in his harem will be portrayed as good or misunderstood and everyone who has a different opinion will be portrayed as evil or stupid or very likely both. Don't forget to give him a cool carrier like assassin, doctor, CEO, or assassin. However, if you feel lazy you can always make him a weeb, but not an obsessed one with communication disorder because that would make him look flawed! Also, remember role=personality, just being the protagonist is enough to substitute for a personality. However, if you want to give him a real personality just make him the personification of pride, greed, and lust. Don't forget to add the personality traits of being handsome and having a big dick! Those traits are very important because they allow him (and by extension the author) to get every woman he wants no matter how incompatible their personalities are because he is a true alpha male. Yes, you hear me right, he is an alpha! Men are naturally divided into two groups. Betas, who are caring, kindhearted men who are not good at fighting, are respectful to everyone around them including women, think before they act, are introverted, like to help people around them, have weaknesses and flaws, forgive others or have any other personality trait that the author thinks is unmanly or makes a person look weak. And then there are the alphas. They are the kind of men that can do everything they want whenever they want. They get all the girls without any effort, they will make fun of harem protagonists even though they themself are just as bland as them but somehow even less likable, they will face-slap everyone who only looks at them the wrong way, they will never forgive anyone till they kill even his soul, no matter how many horrible things they do people around them will still like them and they will get no repercussion for their actions. Basically, alphas are the unholy love children of Mary Sues and Chinese protagonists from cultivation novels. As for the rest of the characters? Well, who gives a shit? The only character who is important is your protagonist and all other characters are just tools to show how great he is. All the female characters who are remotely attractive will only serve to fall for him and show how manly your protagonist is. All villains are only there to get one-shotted by your protagonist to show how strong he is. And the MC of the anime worlds you sent your protagonists to visit will only be there to be outshined by him and to show how cool and badass he is in contrast to them who have flaws that make them feel at least somewhat human. No matter how interesting those characters were in the source material, in your fanfic they all will be shallow copies of the originals so your protagonist can look better in comparison.