For a writer, "the Other" is anyone whose reality you have not experienced.   If you are a white male middle-class U.S. citizen, age 40, the Other includes all females, all persons of color, all the "1%",  all the poor, all non-U.S. citizens, anyone older than 40 (you haven't been there yet) and anyone in an occupation you haven't had or in a place you haven't lived.  That's a lot of "Other."   You know something about people in many of these categories, but you haven't experienced them yourself.    If, on the other hand, you're a second-generation female teenager of Cambodian parents,  you also have a lot of "Other"--everyone who isn't like you in background and experience.   We all have a lot of Other, when you think about it.

Most of us tend to take the easy "Others' when thinking of writing them--the opposite sex, or a sexual orientation that's not our own, or maybe (if daring) someone older or younger.   There are reasons why we don't step outside our own background/experience "neighborhood" to write the Other, and one is the very real fear of doing it wrong.   We know, from reading or from hearing about it, that writing the Other can make the Other angry, contemptuous of our work, and bring down a Twitter-storm on us...even if we try to do it right.  But we live in a diverse world, where seeing, hearing, touching, smelling Otherness is a daily experience.  To leave that entirely out of our writing, even in fantasy fiction, means leaving out a big part of reality.   So...what can we do, without ending up under a dogpile of hate? 

One thing we can do is use our ears and eyes with the mental filters turned off.   You know how, when you see an Other on the bus or the street, and the Other is obviously Other, your mind goes to the things you've been told by your Sames about this Other?    "Oh, yeah, that's an Other all right...look at the way he/she walks...and that [hair/hat/dress/suit]!  You can tell he/she thinks he/she's better than everyone else..."    You hear the loud voice, or don't hear the too-soft one, and you don't really listen to the meaning behind the words.   I was on a train once in England with my son--tourists heading for somewhere still hours away--and at one station a lot of big, loud men wearing football colors got on.  I had heard, of course, about riots at football games.  I was scared.  They were so loud, some of them smelled beery...but when I listened, the loud talk was friendly, teasing each other, affectionate about their families (one had brought his young son--younger than mine--to what would be the boy's first football game.)   We had been sitting for an hour or more on that train, so I offered to stand and let the little boy sit; his father said no, that was OK, the boy was too excited, and then...they asked where I was from, and soon we were having a quieter conversation amid the other noise.  At the next station, where we needed to change trains, they moved aside so my son and I could get out with our luggage.  The one nearest me with a small boy had a wife, another child, a parent living with them, a job he was concerned might disappear...and the football game, would be his one outing for weeks.   Another older passenger, who had also been on the train before the men got on, and also got out to change trains, spoke to me as we walked through the station, disdainful of the football fans and asked if I'd been "bothered."  Seemed surprised that I'd been chatting peacefully with one of them.   

We all have opportunities to learn more about the Other, just by listening, observing,  and being willing to accept that the Other's reality is real to the Other (even if we're sure it's wrong.)    We can also read--fiction by the Other, nonfiction by the Other, and works on history, cultural anthropology, sociology (which help with the background the Other may have had, showing us the variety of ways that different cultures carve up and give meaning to human experience.   We can be aware of differences, even at the level of what's in which drawer in a kitchen,  and see them as variations on the them of Human, rather than right or wrong.   (And experience with people who always think a difference is wrong is also an experience of the Other.   A friend's mother who decided to reset my table on Thanksgiving because her arrangement of flatware was right and mine was wrong annoyed me, but by that feeling I got another jolt of what it's like to be around people who feel entitled to make all the rules...and it's material for the writing.  So I could do better writing a character annoyed by someone assuming he/she knew better, and also do better writing the person who was making that assumption.)  If we know an Other well enough, we can ask...and then really listen to the answer we're given rather than defensively trying to "correct" what was said.    And, being writers, we can use those small Othernesses, as well as large Others, to suggest throughout our work that Other actually exists, and should be included.  We can--if we have the chops--take on some of the big, difficult Others in our work  (current obvious problems relating to politics, war, race, religion, gender, class, etc.)  but we can all include the smaller ones, as we come to know them.   We can take on the big stuff directly (so it's very obvious to readers) or subtly, by imagining other  cultures that handle the same thing differently--where, perhaps, race is not an issue but something else is.  Or the racial difference is defined not by skin color but by height or language.)   We can modulate the Otherness in fiction as we do in real life...usually considering some factors of Other more Otherish than others, and we--like our characters--may assume the person who looks like us and lives next door and is a fan of the same sports team is more like us than the person across town (be they richer or poorer, living in a fancy condo or a shack)...until we find out he's been murdering people in his basement and eating them.  ("But he seemed so normal!  Just a regular guy--heck he's a [team-name] fan!")  Or the sweet little gray-haired lady in the cottage with the roses...used to be an exotic dancer in Las Vegas.  Especially if you're sure you know enough about the Other you're thinking of writing...think again, and look deeper.  Feel deeper.  Try to imagine what life is for that person, or group of persons.  You may still be wrong, but you'll be closer.