I don't think you can do that at all cause what appeals to some people makes other people drop it. People say disney movies appeal to everyone but I haven't watched a movie from them since god knows how long. You can't get everyone.
As people have said, it's impossible to make something that appeals to everyone, but for the lols, if I was told with a gun to my head I had to make the most broadly appealing thing possible, here's what I'd make....
It's an adventure story set in a medieval sort of Fantasy world with a Lord of the Rings sort of aesthetic.
About an attractive young white man who discovers he has a great destiny and gets some kind of special magic sword or artifact.
He has a cool older mentor who is PoC because that's progressive, but not TOO progressive, wouldn't want to upset anyone, but this way nobody can say "all the important characters are white".
He's in love with a beautiful elf princess who can fight a little bit with her bow or magic, but not too well because that'd upset some people, she definitely needs to not be as strong as the hero and to need rescuing on exactly ONE occasion (because if she needs rescuing more than once, she "needs rescuing all the time" and is "annoying", but once is okay).
But while he has a clearly hetero intended main romance, he also has a male companion or frenemy who is super-hot and he has sexual tension with and it's totally shippable, but it'll never actually play out, it's just queerbaiting to keep the people who are into that reading.
He takes his shirt off at least once to show his amazing abs, so the people who are into dudes can ogle, but for people who aren't into dudes it's like... aspirational/power fantasy because this guy represents you!
There are lesbian minor characters to keep the lesbians happy and to make it lightly progressive, but they're both hot femmes and it has no story impact or social commentary so it doesn't upset anyone too much.
The bad guy is an evil lord of an evil empire that wants to take over the world and enslave everyone or something, nothing that might be politically outrageous to anyone. His army is made up of undead skeleton soldiers who are grateful to be killed because it's a release from service, so it's GOOD that the hero slaughters his way though armies, you can enjoy the spectacle of violence completely guilt-free without having to think!
There will be a SHOCKING twist where the hero discovers that he is in fact actually in some way related to the villain, let's go with... he was actually created as a magical clone replacement body for the evil lord and was spirited away by his mentor figure who was one of the evil lord's knights and has been trying to atone ever since. The mentor dies almost immediately after imparting this info.
In the end, the hero overcomes the villain partly due to the villain's own hubris and the oppressed village folk rallying behind the hero and he takes his place as rightful king and unites his kingdom and the elf kingdom and everyone lives happily ever after.
There is an actual industry term for this in Hollywood, called the four quadrant movie!
In essence, demographics are broken up into four quadrants: male and female, over 25 years old and under 25 years old. Movies will try to hit at least two of these quadrants, but the big blockbusters will try to hit all 4.
What’s the formula fo a four quadrant movie? Here are some elements from screencraft.org1
- A “high-concept” premise. Whether it’s a superhero’s adventures, an amazing fantasy, a sci-fi quest , or a compelling true story, four-quadrant films live in this realm: an irresistible story idea that can be grasped in one or two sentences.
- Heroes and villains. That doesn’t mean heroes are flawless or villains can’t have a sad backstory, but concrete-thinking kids struggle with too much complexity in characters. You have to find the balance.
- Plots filled with EMOTION, ACTION and DANGER; and yes, that probably means violence and/or death. The trick is to find the right edge without crossing into inappropriate territory. And thus comes another potential shocker…
- Chuck the G-rating! Unless it’s animated, nothing is perceived as more boring to the moviegoing kid than a G-rated movie. The film must have enough edge to go beyond, but again, not too far.
- Theme. Kids and adults both like a story that says something and has genuine resonance, whether they can articulate it or not.
- Humor. Comic moments always enhance enjoyment, no matter how serious the story might be.
- Kids in lead or major supporting roles. Including kids of course targets the “young” quadrant but also adds new levels of dramatic tension and/or comedy for adults. And let’s dump that “child protagonists can’t carry a film” idea for good! Harry Potter, E.T., Super 8, The Wizard of Oz and more say otherwise.
- A-List stars in some roles. Stars still open movies, particularly with the right packaging.
- Hints of romance. Except for the rare, truly committed misanthrope, everyone responds to a well-done love story; it’s universal. Even 9-10 year-olds (particularly girls) enjoy a bit of titillation here, and the adult quadrants love it, but again, striking the right balance re tone and content is important. Stop at innuendo and kissing.
- “Big-budget” not necessary; in fact, five of the above films were made for $50 million or less, and three of those for under $30 million.
Of course, just because you hit all these elements doesn’t equate automatic success, as many a blockbuster flop can attest to. There are also exceptions to the rules. Still, this is a general guideline if you’re looking to make a broadly appealing work.
I don't think it's possible.
Best you can do IMO is included as much as possible without reliance on cliches tokenism by investing in characters and situations as best you can, whilst leaving plenty of room for suggestion in other areas to keep people interested and guessing, then offer plenty of material that's stand alone in it's own right, so people can pick up at any time without returning to the start, like a soap opera?
Interestingly, this question actually fits me a lot 
I do actually try my best to appeal to as many readers as possible. Do I have more than two main characters? Yep! I have 20 lol! All are very diverse and unique. And while the first book heavily focuses on one character, slowly as the books come, they all will get their time to shine. I honestly believe that representation is really important in story-telling, especially in this time and age when everybody is so divided. It's really important to show that everyone matters. Plus the diversity in my story isn't forced either. It makes canonical sense why everyone is the way they are. Plus, the power system in my story "spirit" heavily enhances their "Individuality" hence the title of the story 
but I do not like to call it "pandering". Calling it that is actually pretty offensive to someone who genuinely cares about inclusivity. I am not pandering to anyone, I am merely writing what I want. Not sure if you are interested but if you are, here it is.
I don’t think a long form story can do this. Too many opinions, and characters, actions or personalities are likely to turn some people off. But typically a short story, can have a very wide appeal. Certainly nothing can appeal to everyone. But something like Shirley Jackson’s “The Lottery” is fairly well known, and it’s not everyone’s cup of tea, but people usually will read the whole thing, and want to talk about it, which is appealing in and of itself. Since you can’t appeal to everyone at least make something worth reading, discussing and that you personally like.
It's only offensive if you think it's offensive. No one is calling you out on creating a huge diverse cast. But if someone wants to create a huge diverse cast just to please everyone and hit every possible person, then it is pandering. Nothing really bad in its core too, but it is what it is.
I didn't say that anybody was calling me out. How would they? I'm not well known here or anything 🤣 I am just saying my opinion on the matter. And since the word pandering was mentioned, I just said what I thought about it. And yes indeed, that is how "being offended" works. Not everyone is offended by the same thing, which BTW, I am not offended if you think that is the case. But if someone were to point at me directly and said I was pandering than yeah, I wouldn't like that. That was the point I was making.
Oh and yes, there is a lot of bad in the core of pandering. Just by the definition, it's an immoral or distasteful thing to do. So not sure what you were trying to say there.
You don't. You make what you like, and target it at people who like what you like.
If you make a story containing homosexual characters, homophobic readers will be turned off.
If you make a story without homosexual characters, homosexual readers may feel disinterested to read it.
If you make a story without violence, gore fans may get bored.
If you make a story with violence, readers who only like romance and comedy will be disinterested.
If you make a story that has everything, it will only appeal to people who have no problem with anything. And those aren't everyone.
So, theoretically, while you CAN have everything in your story, it won't catch the interest of everyone, because some readers do NOT want a story to have everything. Remember that 'a jack of all trades is a master of none'.
Also, if you DID make a story that has everything and everyone would be inclined to read it, you need to have the appropriate quality to keep their interest.
Agreed. A creator's story should be about what they want to make and what they want to say, not about ticking boxes.
I just mean if someone has chosen to view your story, they probably already like some aspect. If nothing appeals to them then they would probably just pass over it. I have a comic that is BL romance with a sci-fi twist. No one who reads my comic complains about it, but I know that someone who doesn’t like BL or romance probably won’t read it. Or someone who DOES might put it down because they don’t like sci-fi. Just putting a bunch of things into your story for the sake of appeal can backfire. Something that one person likes might really turn off another.
Just don't, you cant please everyone and cant pander to everyone, just write and create characters that suit your tastes
The only time I have seen someone pull it off is when the media is wholesome enough to appeal to some one as young a 4 and as old as 90, while being silly/mature enough to appeal to teens and young adults who want something that is not only for kids.
A good example is Toy Story 3.
You might be surprised. I feel like there is a lot of crossover between media that appeals to straight women and gay men. There has also been media that was meant for a female audience but gained a large male audience, like My Little Pony: Friendship is Magic. And there has also been media meant for a male audience that gained female fans because they thought the male leads were cute.
It's impossible to appeal to every single human being, because people have different tastes and some tastes are incompatible to each other. Everything is liked by some and hated by others.
I don't agree because I remember a few successful writers saying that their story is 50% for them, and 50% for their audience, one of them even said that they audience have a bigger percentage. (that last one isn't a writer tho, he's a mangaka)
Here's the thing -- you're assuming what has worked for them could work for you or anyone else.
Never assume it'll pan out the same way just because it helped a few people get famous.
Their journey is not your journey.
If pandering to everyone worked all of the time, my response would be different. But as many have said -- you can't. You simply can't. You will break your spine trying to bend over backwards for everyone, banking on the hope that they might read your work or might support you with money.
Another thing -- readers are not stupid.
People can tell if someone is trying to pander to a demographic rather than make a story they enjoy. People can tell if someone is only in their fandom for popularity and money. Some creators are better at hiding it than others, but over time, it becomes apparent when someone doesn't like the work they did (and still don't like it). If you're gonna go to all that trouble trying to make people like your stuff, you might as well enjoy some part of it.
Because if you're doing this just to appeal to people and make money, and don't include the things you like -- you're in for a long, disappointing journey.
Edit: Also remember -- we're all consumers. We like and dislike media just like everyone else. Being a creator doesn't change that. And if others cannot always gather our attention, why should we break spines trying to do the same? Some people just won't like what you put out -- it be like that.