@Mindysan33 hit most of the big points. The best solution is to hire more POC and female developers because they'll be offering authentic, lived experiences which is the most valuable tool in making diverse characters.
The other is to understand that western society sees whiteness as the default. In fact, I'd argue that this is now a global concept because of imperialism. Mindy touched upon this when she mentioned that minority characters aren't seen as "real" unless they ascribe to a prescriptive archetype.
Minorities are viewed through a binary lens. An Asian guy is seen as either representative of his entire race or an outlier. A sexless Asian nerd on TV is seen as representing all Asian men. It's how you expect an Asian man to be portrayed. When an Asian male character who is sexually active and confident comes along, it's viewed as (1) inauthentic, (2) atypical ("a bad Asian"), or (3) pandering. This is all rooted in the assumption that sexually active Asian men or confident Asian men don't exist, or rather, they shouldn't be allowed to exist. Asian workers who display dominance in the workplace are viewed as uppity by their white peers because it doesn't fit the narrative they have in their heads of how Asians are supposed to act.
Meanwhile, white characters and white people are seen as individuals. None of them are ever avatars or outliers. When you see an awkward white nerd on TV, no one sees a white nerd. They just see a nerd. When you see a white gangster on TV, no one sees a white gangster. They just see a gangster. There's no inherent racial association with emasculation, criminality, or deviancy when it comes to white characters.
Now, all that said, how do you make interesting minority and female characters? Easy. You write them, first and foremost, as individuals.
I did a Q&A a few weeks back with Scott Alexander, the head writer who handled the Shadow Warrior reboot. I hated the original game when I was a kid. To this day, it's still one of the most appallingly racist titles I've ever played. The original Shadow Warrior derived all its humor by turning Asianness into a minstrel show.
Which is why I was so impressed with how Alexander rebooted the series. Usually when stuff like this gets rebooted, the characters in question get whitewashed (as was the case with The Mandarin in the Iron Man movies), alienated so far from the source material that it might as well be a new character, or completely shelved altogether. The new dev team managed to find that sweet spot of presenting the new Lo Wang as a fully humanized, engaging character without compromising his Asianness.
How'd they do that? Well, they did away with the short hand racial stereotypes used to describe the character. You get shitty characters and stereotyped characters when you build from the outside in.
Who was the original Lo Wang? Well, he was Chinese, he was really good at kung fu, he used samurai weapons, and he was arrogant. If you start building a character that way, then you end up with a snowball of even more problematic traits, so the original Lo Wang was also incredibly sexist (preying into western notions of misogynistic Asian men), arrogant, and macho.
Wild Hog Studios decided to take the opposite approach by building him from the inside first. Okay, so first step, toning down those racially charged yellow peril undertones from a time when the white world thought hordes of Chinese men would rape all the white women and establish a Chinese world order. That absolutely has to go.
But being an arrogant, macho dude is kind of Lo Wang's appeal, as well as his Asianness. How can you preserve those qualities while keeping him from feeling too over-the-top? Well, you put him down a peg by introducing a companion character who constantly makes jokes at his expense. That way he can't ever get too cool or macho, and it's in those moments where Lo Wang's humanity comes out. You see his inside, not just his outsides.
The new Lo Wang is a bombastic action hero in the John McClane and Bruce Lee sense, but like those heroes, he also deals with personal struggles. Throughout the game, Hoji is speaking through Lo Wang's head, constantly scrutinizing everything he does. Sometimes he makes Lo Wang feel like an ass, and sometimes he's surprised when he sees Lo Wang in some moments of vulnerability and tenderness. Lo Wang might be a demon slaying badass, but he still embarrasses himself by messing up simple tasks and feels guilty for letting down his friends. We may not all be demon slaying badasses but everyone can relate to those things.
And to top it all off, Shadow Warrior 2013 turned Asian culture from being the butt of the joke to the central appeal of the game. In 2013 Shadow Warrior, being Chinese is part of why Lo Wang is cool. It's why his weapons are cool. It's why the mythology of the world is cool. It's the same reasoning behind The Boondock Saints -- Conner and Murphy are cool because they're Irish. Their Irishness is never treated as something to demean and laugh at.
True, but as a geek of color, I gotta say, I'm getting pretty sick of fantastic racism. One of the running jokes among game journalists is that videogames are the only medium where you'll see more orcs, dragons, elves, robots, and aliens than you will women and minorities.
The trope itself is not inherently bad, but it's just so overdone. Okay, so your game is exploring themes of bigotry and prejudice using make-believe creatures. Yeah, you and 5 other titles this year. Part of this is because the cultural diet of most game designers has been typical geek shit -- sci-fi, fantasy, anime, pop action films. That's why you never see games about sex trafficking or police brutality or domestic abuse, but there's no shortage of games about a post-apocalyptic world or "the depravity of man" or whatever.
BioShock Infinite came really close. Before release, Ken Levine was bragging about how the game would be exploring all these touchy social themes like Manifest Destiny, systematic racism, religious fanaticism, and American Exceptionalism, all very relevant issues today. Awesome! Then when the game came out, it turns out all that was just advertising fluff. All those themes get completely dumped by the second half of the game when it becomes about infinite universes and different dimensions, so in the end, BioShock Infinite was yet another typical geek game.
Like, it's insane how we've never seen a game like We Are Chicago until now, but I can name a dozen games featuring Space Jews or the Trans-Elven Slave Trade.
Write women and POC characters with the same consideration that's given to white male characters. Treat them as individuals, which means you're building them from the inside-out. Often the best way to achieve this is simply hire more women and POC artists.