We live in a big world full of lots of different kinds of people - over seven and a half billion as of May 2018. Writing a novel (or short story, or anything, really), requires the author to focus on a much smaller population.
It's super easy for writers in the United States to default to having an all white cast. So how do we overcome this habit?
By taking a look at the world's statistics! I consider using these numbers as a good set of training wheels to help you until you write diverse characters in a more natural, intuitive fashion.
I always start with my geography - where does my story take place? For example, if you set your work in the United States, the racial population estimates for 2018 are:
60.7% Caucasian alone
13% Black alone
18% Hispanic alone
5.8% Asian Alone
2.7% Biracial
1.5% Indigenous, including Hawaiian, Native American, and Pacific Islander
When you are writing a story, take a glance at these numbers and go, "Oh, yeah. Let's not forget the rest of the population!" It's okay if it feels a little weird at first. I know that I'm not very good at things in the beginning. It'll become more relaxed quite quickly.
Is your book going to take place in an international setting? Take a look at the world population.
Chart shamelessly stolen from Science Chat Forum
If you don't write people from Asia (Chinese and subcontinental Indian, especially) wandering your setting, you are really missing a huge portion of the population. For example, when I traveled to Istanbul, I stuck out because I was tall. I was constantly afraid I would run into a petite Asian woman by accident. When I wrote about my characters being in Istanbul, I made sure to comment on how very diverse the city is. If I had pretended that there were no world travelers in the huge city, I would have been doing my readers a disservice.
Maybe you accidentally said something racist or sexist. You hurt someone you never meant to hurt and you've been called on it. (If you've done something mean or cruel on purpose, this blog post is not for you)
Now what? I know you want to defend yourself, to clarify that it was a mistake you don't usually make. So, here's a handy primer for when you messed up.
First things first. This is what you say:
"Wow, I screwed up. I'm sorry. Thank you for telling me and I will do better in the future."
And that's it. That's all you say. You stop talking, you don't defend yourself, you don't explain. Just take a break. Once you've calmed down from feeling bad and/or defensive, do some research. Look at the people who are taking the time to educate you.
Start with reading The Invisible Knapsack, especially if someone has said you are coming from a place of privilege. This essay carefully explains what exactly that means.
I've always seen privilege as a river of sewage running through our ideals of equality. People like walking in the middle of all that hate because it's warmer and the current can take you further. If you manage to escape the current and start walking to the beach, you start off feeling colder and slower at first. Then you realize how much better the world smells, and how much more fun you are having with all these neat people.
Of course, we all still slip up or fall into an unseen deep spot. When you apologize and step back, you give yourself to wash off the garbage and see what happened when you are more clear sighted.
(I do know that being able to step back is a privilege in and of itself.)
While you are researching and thinking, try to remember a time when you experienced true equality. I like to think of going to a George Clinton/Parliament concert. Even though I was queasy from all the pot smoke (I'm allergic), I got a glimpse of at what one nation under a groove could do. We all danced together - no self-segregation. Everyone was smiling at each other (the pot might have helped, but the music was what brought us together). I had NEVER seen everyone taking up equal space on the dance floor. This show was a harbinger of hope.
Lastly, when someone says they have experienced racism, the best way to make them feel better is to give them loving human contact. In a real way, they are grieving a lot, especially one of trust. Buy them some croissants (or whatever. You know what they like) and do something nice together.
In the end, the best way to keep combating racism is to be real and honest with each other.