In a guest post on Jane Friedman’s blog, Tiffany Yates Martin offers advice for weaving flashbacks into your story without breaking your narrative.
“Authors often think of flashbacks as separate, self-contained scenes that serve to fill in essential backstory for characters—and sometimes this can be their format and function,” Martin writes. “But this separatist approach is often at the root of why flashbacks can be so tricky for authors to incorporate without pulling the reader out of the smooth flow of the story or stalling momentum, and why they may wrestle with smoothly moving in and out of a flashback.”
Instead of treating flashbacks as standalone sequences, you should strive to give them context within the overall narrative by attaching the flashback to something happening in the present, ie: something that triggers the characters memory of the past events you wish to relate. To tie the flashback in further, something from the past should spark an action or reaction in the present. Making these connections will help your flashback feel organic and necessary, and your transitions will be less jarring for the reader, if not unnoticeable.