On Characters
There are four really, really important things to remember about characters:
Characters are people. (Yes, even if they're aliens or elves or talking rabbits.)
People, and therefore characters, are all the same.
People, and therefore characters, are all different.
Most important of all: Every person, and therefore every character, is an individual.
Taking these assertions in order: Characters are people because readers are people, and because writers have to work with human languages. I've seen the occasional attempt to write a "truly alien alien," and every one ends up being incomprehensible. Even if one trusts that the writer has actually managed to get his or her brain wrapped around a "true alien," getting it across to a reader in a story just doesn't work (except, of course, where the whole point is the utter incomprehensibility of the alien).
Stories start from where we are, and where we are starts with being human. "Truly alien aliens" are interesting and make interesting stories when humans meet them and have to cope with them, but the focus ends up being on the humans. The alien becomes less a character than an intriguing, unsolvable mystery. When the story gets told from a nonhuman point of view, the alien or rabbit or whatever has to have enough overlap with recognizable human wants and needs to be understandable, or there's no story.
Which segues neatly into point #2: people are the same. This is why we're still reading the Illiad and Romeo and Juliet and the Ramayana and the Tale of Genji, even though the writers who produced these stories lived in totally different times and cultures from our own: the stories speak to universal human themes and wants and emotions. Everybody hungers, loves, wants, fears, wonders. Every human culture has clear notions of what is right and what is wrong, what is done and what is not done. Exactly what it is that is done or not done, feared, loved, wanted, etc. varies from culture to culture and person to person, but the basic urge is common to us all.
And that variation brings me to point #3: People are different. Different cultures place their highest value on different things: individuality vs. the good of the community, or independence vs. obedience to authority, for instance. What is considered polite varies; what makes for high status varies; which people are held up for admiration or vilification varies. Within a culture, different subgroups are treated differently and thus have different life experiences that make those people think and react differently from people in other subgroups.
Even when nearly everything lines up - background, age, gender, culture - no two people are exactly the same. My sisters and I are very far from having the same wants and fears and so on, even though we grew up in the same family, time, and culture. Even my identical twin cousins, raised in the Alaska bush, are not perfectly interchangeable in their tastes and ways of thinking.
There are writers who get stuck at point #2 - all their characters are the same. Oh, they look a little different, but when it comes to personality and the way they react to things, the way they speak and think, the fact that A is an elf, B is an autistic teenager, and C is a polygamous 200-year-old alien makes about as much difference as the fact that they each have different colored hair.
Oddly, points #2 and #3 are often problems for the same writer, sometimes at almost the same time. A writer considers some group - modern teenagers, women, men, trauma victims, racial or ethnic minorities, rednecks, Christians, pagans, gays - as "too different" to understand, while also being exactly alike within that group. This usually results in the writer avoiding having characters that are, say, rednecks (because they "can't write rednecks" - i.e., they're too different), or defaulting to stereotypes (because "all rednecks are like that") when a particular story forces them to have a redneck (teen, woman, man, minority, etc.) in the story after all.
I think most of these problems happen because these writers lose sight of point #4. They forget that they are not writing about a group of men, a group of rednecks, a group of gays or Christians, a particular minority. They are writing about George and Chuck and Shaku and Mary Lou; Aki and Robin; Marge (never Margie!) and Shawn and Caitlyn. They are writing about individuals who share a common human heritage (or at least, enough human characteristics to interest the reader, even if they're rabbits) and a variety of unique life experiences that shape their personalities and fears and desires.
"What would a disabled-person/teen/Christian/man/rabbit do in this situation?" is not a relevant question for any writer; the question should be "What would Chuck (or Caitlyn or Aki or Robin) do?" The answer will not be shaped by only one of the groups that person belongs to (Chuck is, perhaps, a Christian as well as a teenager, a soldier, a father … the list could go on, and all of those things will factor into what he does next).
Writers who wish to write realistic characters have to avoid the trap of defining their characters (even the secondary characters) by only one aspect of what they are. They have to remember that characters are people. all the same, all different, all unique individuals with bits that overlap with other characters and bits that don't.
