Quiltbag Spec Fic?

I'd just make it part of the character, like black hair or not eating broccoli.

Elizabeth Bear does this well; so does Nicola Griffith.

I "balance" it the same way I balance straight characters/relationships.

I think it's going to depend a lot on your world. Is it a speculative world where queerness is completely unremarkable? Or is it closer to our world, where it's considered out of the ordinary and will be remarked upon?

Just look at the story you're telling. Is it important to the story or character? Will there logically be conflict, given the plot and characterization? If a character is closeted and about to have her first girlfriend, then it might be unrealistic to gloss over the conflict this might cause. Other times, if a character is open and lives in an accepting environment, the fact that the character is queer might not garner more than a few off-hand mentions.

There's not going to be any clear answer. Different stories need different approaches, different characters have different priorities, and different readers have different preferences.

I almost exclusively write fantasy (and occasional sci-fi) starring queer characters. As others have said, it really depends on what your world is like.

My major project is set in a world where it's a given that most people across social classes will at least experiment with queer relationships in youth, but since it's still a mainly patriarchal world and since most people marry for practical reasons, married adult couples tend to be heterosexual.

There are countries where religious texts are interpreted to show that one of the gods was female but kept a harem of women, and that has evolved over the centuries into a law allowing for women to act as men in society if they partner as adults with other women.

Because the gods are essentially human, most cultures accept the idea that they might make mistakes, so trans* people tend to be accepted. On the other hand, gender roles remain rigid among the upper classes, so non-binary characters are frowned upon.

There's one country where it's turned from an open secret to a tradition for the king or queen to have a same-gender "adviser" who is sometimes just a friend, but often a sexual partner. There's an idea that since the genders are different, a good ruler should have input from both (which, again, doesn't allow for non-binary characters).

All this is tentative and imperfect, but my point is, you can present your QUILTBAG characters however you like as long as you give context for why they're presented that way. If your universe is generally open-minded, the intricacies of the characters' lives and identities don't matter more than any physical trait. If your universe has strict laws and social norms, the characters' identities will probably be wrapped up in the conflict somehow.

I have a steampunk series with an alternate history where America is a near-utopia. Slavery was abolished in the American Revolution, and homosexuality is generally accepted, and Native Americans live in harmony with white, black, and other cultures. I have Native American MCs and talk about the acceptance of one character nicknamed Two-Spirit. All four MCs are gay, two guys, two girls, and they are two couples, and for the most part there is no conflict, but they know if their enemy takes over they will be oppressed, and one character is scorned by his father for wanting to marry his boyfriend because the father wants him to bear a child, and in those days there weren't the options we have today for two men to have a baby. (Well, I have actually learned that two-spirited people would care for children and possibly even adopt orphans, but Strong Arrow would still not be able to bear a child of his own DNA without a female.)

It depends on the WIP and the setting, for me. Sometimes it's an issue. Sometimes it's not. My urban fantasy, it's going to be an issue with my bisexual heroine and her fundamentalist parents.

My... well, what I'm referring to as my Middle Eastern Renaissance Steampunk, the culture of my city-state where the stories take place simply doesn't care. All relationships are equal (including polyamorous ones). The Queen's Consort is a woman, and the culture is matrilineal. I haven't decided yet if there will be a magical way for gay couples to reproduce (or for trans characters to transition; a large part of this is not really having a solid magic system yet... I have more on the science side!). Half or more of the cast of main characters in the series are queer or trans and it's not treated any differently, at least in this city-state. Other countries in the world setting are homophobic and transphobic, and as the city-state has open immigration (for now; immigration is actually a political issue because it's a small city-state and they are dealing with issues of overcrowding because it's a "Land of Milk and Honey" type situation), some of the main characters are dealing with issues from being queer and having grown up in and lived in homophobic countries.

But for the characters that grew up there... the relationships are still important, and being queer is part of their identity. It's not window-dressing; it's part of who they are, just as much as being heterosexual is part of someone. But it's not a great source of angst. As a queer person myself, I personally get annoyed seeing Every. Damn. Book. be about angst and how awful it is to be queer... I just want to read about some queer characters who just happen to be queer, dammit!

And you know, I actually don't think "wallpaper" is necessarily bad, assuming you're not doing anything offensive. People don't make a big deal about straight characters being straight. It would be nice to see more work where people don't make a big deal about queer characters being queer.