To be honest, I can't be sure if I've written a piece solely on the subject before, so I'm doing it now. Possibly again? I don't think so, though.
Anywho, LGBTQA+ in fiction. First, there's not enough in mainstream fiction. It's getting so much better, because people are losing the fear of speaking up, but it's still not great. Mostly, it's not great when cis-het people write about it. Mostly. Some, obviously, get it right. Many do not.
Problematic Writing Faux Pas 1 - LAZY AS FUCK WRITING
Part of the problem for cis-het writers writing LGBTQA+ characters is that they get so, so, so, so fucking lazy. They fall back to ridiculous stereotypes and stupid tropes instead of treating LGBTQA+ characters as full, complex human beings. They turn them into caricatures.
Writers, LGBTQA+ people are just that: people. Write them like they are people.
Incidentally, this is a major problem when writing women and disabled characters too. In fact, all of this applies.
Problematic Writing Faux Pas 2 - THE QUEER AGENDA
Yay. Good for you. You are being a little more inclusive in your writing. Good. It's a start. Now here's a truth bomb: LGBTQA+ are whole people, and no two are the same. They have a variety of interests, personalities, perspectives, faiths, opinions, and so forth. They are not a monolith.
There is a persistent problem with representing LGBTQA+ as all one kind of person. This bleeds from the LAZY AS FUCK WRITING mentioned before. Once again, writer, write these characters like they're actual people. Not every queer person is empathetic or sweet. They're not all villains, seeking to destroy society, either.
Problematic Writing Faux Pas 3 - LOOK! I HAVE A QUEER CHARACTER, GUYS! LOOK! THEY'RE QUEER!
This is perhaps one of the most egregious of the faux pas when writing LGBTQA+ characters, and that is the tendency to make a character's orientation or gender identity their entire character. Guys, guys... THEY'RE WHOLE PEOPLE. WRITE THEM LIKE THEY'RE PEOPLE! Their queerness should be written like straightness; which is to say, part of who they are, but not what defines them.
Making their gender identity or sexual orientation their defining feature robs them of personhood. It denies them the same kind of complexity given to straight characters, and that's just not on.
Problematic Writing Faux Pas 4 - THE QUEER PLOT
Including LGBTQA+ characters is a great. Making one's protagonist LGBTQA+ is fantastic! Making the story all about their queerness is not. Much like the LOOK! I HAVE A QUEER CHARACTER, GUYS! LOOK! THEY'RE QUEER! problem, this one is all about making everything in a story revolve around a character's queerness.
I've heard this reflected in statements like, "If you're going to make a character queer, make it matter."
Come on! Writers should be better than that. No. Don't make it matter. I shouldn't matter in anything except who your character might be interested in (or not, if they're asexual). Alan Turing did not break the enigma code because he was gay.
The idea that there must be some sort of justification for including LGBTQA+ characters is utterly stupid to me. There are no such justifications for making a character straight. There should be no requirement for making a character queer. It boggles my mind and boils my blood that some people think there ought to be.
(Incidentally, I got distracted as I was writing this by a blog post by Chuck Wendig, which was a recap of a Twitter rant where he says pretty much what I'm saying. You can read it here. He does it better than I do)
That said, sometimes a person's queerness does have a place in the plot (it could be a forbidden love story, for example, where queer love is frowned upon... so... uh... set today, I guess. God, now I'm depressed). But to demand that any inclusion of LGBTQA+ characters be justified by the plot in every instance of inclusion sounds as ridiculous to me as justifying the inclusion of women, or straight characters, or brown characters.
All of which to say, LGBTQA+ people are people. WRITE THEM LIKE THEY'RE PEOPLE.
If you are unable to, or if you refuse because "it's too hard," then you are, in my opinion, a shoddy writer.
Clue: Writing is hard. That's why not everyone is a bloody writer.
So, by all means, be inclusive in your writing, but for the love of all things good and green in this world, do it right. A good way to judge whether or not you're off course, is to turn your character cis-het. If what you're writing sounds weird when its about a straight person, change it.
Also, you can apply this advice to writing women, disabled characters, or people of colour.
Incidentally, one of my favourite YouTubers put out a video of him and a bunch of LGBTQA+ friends answering questions. It was sweet and emotional, funny and interesting. Writers, consider this part of your research: