Have you ever read a book where every character sounds the same? How about one where the main character has a set of beliefs that they work into every conversation? You might be noticing signs of an unfortunate foible of writers: injecting themselves into their characters.
The best character are the ones the reader can believe are real. By making them into puppets for their own beliefs or personality, the author risks breaking that magic spell over the reader. How do you avoid falling into this trap?
Know Your Characters’ Beliefs
It’s easy to fall into the trap of writing from your own perspective. You see a scene in your head, and you have characters within it, but you’re not there. Your characters are, and your readers will be, but you are just an observer. When you’re writing dialogue, you are essentially talking to yourself. In normal folks, this is something to raise an eyebrow at, but for a writer it’s all in a day’s work. The key to remember is that you are not talking to yourself. You are acting out two parts of a play, acting both roles, and writing down the results. The two (or more) characters are not you. You are their spokesman, their interpreter, their stenographer. When one character asks another , “Why should I do this?” don’t give the answer you would give. Consider the respondent’s personality, background, beliefs, and relationship to the questioner. This should tell you what sort of answer they need to be giving.
Get Off Your Soap Box
Unless you are writing a piece specifically to espouse a set of beliefs, leave the preaching out of your writing. It can be jarring to hear a character making everything that happens to them into a parable, and it can be especially jarring when you might wonder why this character would even hold such beliefs. It’s easy to flip the table on this one as well, and create characters as straw men just to shout down opposing views.
Anyone is welcome to write agenda-driven fiction, but just be aware that your views are going to sound odd to readers when they echo out of every character’s mouth.
Listen to Places
The more speculative fiction gets, the more you have to work to make people from different geographic backgrounds sound different from one another. On Earth, it’s often easy to tell where someone is from, just based on accent, idioms, and word choice. Just the cola/soda/pop/coke breakdown can give you clues about where someone is from. As a writer, you need to be aware of these differences, otherwise character from New Orleans, San Fransisco, and Chicago might all end up sounding like the they grew up on Long Island (or wherever the writer grew up).
For a constructed world, the author has two duties: remove his or her own Earth-centric regional quirks, and to replace them with something believable in their own world. Do elves’ idioms all involve foliage? Do dwarves refer to themselves in the third person? Do creatures from Rigel VII have elaborate compound contractions? It doesn’t matter how you make people from different places speak, as long as you are consistent about it, and the reader can notice the difference.