Keep it relevant. This is the same as the rule for infodumps. Only tell them what they need to know to understand this part of the story. This is especially true in beginnings, when we don't know the characters or their conflicts yet. The last thing we want to do is jump back into the past and get to know even more characters and conflicts.
Keep it short. Or rather, only make it as long as it needs to be (really, this is just an extension of the first tip). For example, the flashback below (in italics) is only 10 words long:
(from Cunning Folk)How could Suriya lose control like that? Aunt Pern had told her how, as a baby, Suriya’s fire kept them warm at night, but that was a long time ago. For as long as she could remember, Suriya had been able to control her power, even in her sleep – to the point where releasing was difficult simply because she never did it.
Don't be heavy-handed. When I first started writing, I thought I had to make the flashback obvious. Like this:
Five minutes to curtain, and Steve was nervous. He stared at the guitar in his hand--the same guitar he'd played with for ten years. It reminded him of the first time he played on stage...
Can you hear the Wayne's World flashback sound? Don't do this. As long as the reader can tell you're going into a flashback, you can just jump right in: "Five minutes to curtain, and Steve was nervous. The first time he played on stage..."
Same with when the flashback ends. Don't toss in a handful of sentences about Steve looking at the guitar and "remembering where he was." Jump right in. Have a stagehand or something (who was not in the flashback) say, "Steve? It's time," and then Steve goes on stage to his legions of fans. So long as the present is sufficiently different from the past, the reader will have no problem keeping up.
Don't worry about tense. I mean, do worry about tense, cuz you're a writer. But don't feel like it has to be perfect. Technically, when you're writing about the past of the past, you're supposed to use "had" a lot (past perfect tense, for you grammarians). "Steve's first time on stage, he had tripped over his bellbottoms." But in practice, doing this for every single verb is annoying.
Instead, use "had" near the beginning of the flashback as a clue to the reader, but then don't be afraid to back off. Mostly, you only need "had" when the reader might be confused as to when the action took place (i.e. in the present, or in the flashback). "Steve's first time on stage, he tripped over his bellbottoms." See? No confusion.
Okay, for those of you still with me, I have a (multi-paragraph) excerpt from my current work-in-progress. It's a flashback that uses all of these tips...hopefully. If I screwed it up, acting like a better writer than I am, I'm really, really sorry.
(SETUP: It's Suriya's first morning after losing her Aunt Pern and after being chased by bounty hunters through the streets of Chiang Mai.)
No dreams. Thank God.
When Suriya was very little, they had lived in a village where people knew what she was and for a while even liked her. Because of her dreams.
The village was called Umong. Suriya couldn't have been more than six years old at the time – old enough to realize her dreams meant something, too young to keep them to herself. It started when she saved an old man's life. She dreamed he had been crushed by a falling tree. Later that day, when Suriya saw her dream was about to happen, she cried out.
The tree missed the old man by a hand's width.
He had thanked her. The whole village had thanked her. They gave her gifts and roasted pigs in her honor.
Then they wanted their own dreams. Almost every morning, they came to ask what she had seen in the night. She told them with the innocence of a child.
Some nights she had no dreams, and the villagers' reactions frightened her. Sometimes she even lied about her dreams just to make people happy.
Other nights she didn't dream enough. She had seen one man – she still remembered his name was Danilay – lying dead on the ground, but she didn't know where or how. Danilay got mad. He shook her and slapped her until Aunt Pern had intervened.
They left Umong that night. She never found out how or even if her dream came true. And she never told her dreams again to anyone, except Aunt Pern.
Aunt Pern. Oh, God.
Suriya jerked upright. She was still in the strange guesthouse. A soft light filtered through the curtains. Anna sat on the stool watching the morning news.
“Good morning,” Anna's voice came into her mind. She didn't turn away from the TV.
When Suriya was very little, they had lived in a village where people knew what she was and for a while even liked her. Because of her dreams.
The village was called Umong. Suriya couldn't have been more than six years old at the time – old enough to realize her dreams meant something, too young to keep them to herself. It started when she saved an old man's life. She dreamed he had been crushed by a falling tree. Later that day, when Suriya saw her dream was about to happen, she cried out.
The tree missed the old man by a hand's width.
He had thanked her. The whole village had thanked her. They gave her gifts and roasted pigs in her honor.
Then they wanted their own dreams. Almost every morning, they came to ask what she had seen in the night. She told them with the innocence of a child.
Some nights she had no dreams, and the villagers' reactions frightened her. Sometimes she even lied about her dreams just to make people happy.
Other nights she didn't dream enough. She had seen one man – she still remembered his name was Danilay – lying dead on the ground, but she didn't know where or how. Danilay got mad. He shook her and slapped her until Aunt Pern had intervened.
They left Umong that night. She never found out how or even if her dream came true. And she never told her dreams again to anyone, except Aunt Pern.
Aunt Pern. Oh, God.
Suriya jerked upright. She was still in the strange guesthouse. A soft light filtered through the curtains. Anna sat on the stool watching the morning news.
“Good morning,” Anna's voice came into her mind. She didn't turn away from the TV.
