Updated: Jun 9, 2021
In many respects, writing is a meditative process. You sit down, you clear your mind, you focus, then spew forth the thoughts that come to mind on paper. Some people have a ritual and some are a bit more disorganized. Either works if it helps keep the activity fresh.
Writing dialogue adds a layer to the affair. *Practical Aesthetics distances us from the character's perspective. Therefore, another technique should be applied. Or a combination of techniques. What I personally find to be helpful is a lot of homework and preparation.
It is a delicate art writing for another voice. Let me tell you how to best prepare. There are three best practices. First of all, a character's cultural backstory is essential knowledge. Pull from what you know and study the rest. If all your characters come from the same relative geographical location, your lucky. That's all I'll mention for that one.
Secondly, the detail in patterns of speech can be mostly understood through observation. Go out into the world and genuinely listen to people. Write notes on how a friend phrases certain sentences. Write notes on what different slang terms are used by a stranger. If someone says something that you would never think to say, that's a gem. That's a fantastic form of homework.
The final practice is part of the writing process itself. Make a conscious effort for each character to say things differently. Catch yourself repeating words and phrases. Then, replace those personal habits with other options. It's exhaustive work, but it's simple.
A thought to ponder: Some people role play and act out the characters' perspectives. That is a natural talent. It requires the writer to, in a sense, trick their own mind. If you can do it, definitely do it.
That's all. Research, then do. That's my advice for the time being.
*Practical Aesthetics = the technique taught to actors at Mamet and Macy's Atlantic Acting School. I believe that writing a story using acting methodology makes the process more active and less heady. When I mention beats, actions, and throughlines, I am using terminology as it is related to this acting technique.