I've found that writing "character's sexual identity is not the surrounding social standard is" often benefits from giving them birth family who don't quite get it - not in confrontational disapproving ways so much as the irritating little brother who keeps coming up with new ways of trying to understand non-standard in terms of standard and failing, or the parent who is still hoping the character will grow out of it eventually; that can get realistic interactions that set up (1of2)
the characters' identity for the reader without feeling forced. You can also use it the other way around, to establish a fictional society's social default expectations that are alien to your reader by contrasting them with a familiar character (the equivalent of "They said it was coffee, but it was bitter and the carbonation was all gone and worst of all it was hot.") Doing both at once is really tricky, though. (2of2)
a fictional alien societycompletely different from humans'a POV character from that alien societya POV character from that alien society who meets humans and comments innerly on how fucking weird their society isa POV character from that alien society who doesn't quite fit into their own too, like a normal teenager, but instead of switching to human they just compare and contrast and like their own way better but man if we adopted this one custom our life would be so much bettersaid custom being either something absolutely minor that most humans don't even think about, or something that most humans would pay to get rid ofsaid POV character trying to make sense of DIFFERENT human societies, noting differences and similarities, like "but why do they ALL do this???" and "oh my god what ELSE can they come up with"
I'm sorry I got distracted from sexualities there for a moment...
My favorite way of writing / reading about non-standard sexual identity is to write a society that just, like, completely accepts it. Nobody gives a fuck, like, at all. It's no stranger than different hair color. And if it's not common, then inventing some new customs/stereotypes from that culture about that thing that neither match our own nor directly invert them, something like "you are gay? so you are good at math?" "NO FUCK OFF" that subtly hints at how arbitrarily bullshit our own stereotypes are.
Actually alien societies in fantasy&sci-fi are my weakness and love for life... yeah... you must have already noticed this in this post >_>
And I really don't like reading/writing about prejudice that matches that from our own world. It's just. No. I want to read about a badass girl WITHOUT her having to struggle against rape culture and misogyny, thank you, I can get my dose of those from youtube comments any minute, can I pretend they don't exist for at least the duration of this book??? yes, thank you
And same with non-understanding family - my favorite kind of fictional family is the one where everything is fine. Everyone fights sometimes, and gets tired of each other, and there's a certain flair of craziness over everything that happens - newcomers either get sucked into this whirlpool of complex interactions instantly and become new family members or watch from the outside helplessly without understanding a thing... and in the end ALL of this family sticks together, and trusts each other before everyone else, and if someone has a secret, they'll help guard it without even knowing what it is. Ya know... a fantasy sort of family ^)_^
It's just my own preference, of course. The idea of using it to give the audience a sense of familiarity and get the audience to identify with it through the POV character sounds really good! It's just. not my cup of tea.