My latest book has flashbacks written right through it because my MC's present is very much a product of past events. I think this structure works really well because each flashback to the past relates to an event or emotion being experienced in the present.
My critique group disagree. Often loudly. Several of them have told me they think the flashbacks detract from the story because they break the flow and others say they add unnecessary words. Another told me flashbacks are old fashioned and that no modern publisher will take on a book with this structure.
What advice can you give me about using flashbacks? Am I wrong to want to structure my book this way?
To be honest, it's really hard to answer this without having read your book. Flashbacks are tricky to do well, and they need to serve a purpose or they can lessen the immediacy and power of the story.
Read your manuscript with a critical eye and ask yourself if every flashback you've written is really necessary. Is there anther way this information could be imparted to your reader? Sometimes referencing a past event in conversation with another character can give enough of an idea about that event to clue in the reader. Especially if either or both characters have a really visceral reaction to it. Any event worth flashing back to is something that will have ongoing impacts on them in the present, will continue haunting them throughout the story.
If you do think every flashback is necessary, make sure you make it clear to the reader what is happening in the present and what is in the past and make the transitions between the two smooth. If you're jumping between time periods in a single chapter, the reader needs cues to know that they're moving from the present to the past, and then back again. Experiment with using different language in your flashbacks, or if you really are having one per chapter, maybe consider changing the structure so you alternate chapters between past and present. Although that may not work if the events you're flashing back to happen at random points in the characters' lives rather than in a single period.
My book Chasing the Taillights had flashbacks in almost every chapter when I first drafted it, but as I worked through the revision process, I realized most of those flashbacks were unnecessary, except for one long one toward the end. The others could all be conveyed through the characters' internal thoughts and their conversations with others. By cutting out all the unnecessary flashbacks, I managed to cut the wordcount of the book by about 20K.
So, my overall advice about flashbacks would be to only keep the ones that are really needed for a reader to understand and engage with the story, to keep them as brief as possible where they are needed, and to ensure the reader is well cued when you are moving in or out of a different time period.
And one more really important thing to remember: don't put a flashback in your first chapter. The first chapter is for introducing your characters and the world they are currently living in. You can hint at past events, but save the flashbacks for once the reader is well bedded into the world and starting to be invested in the characters.
Hopefully that is of some help.
Good luck with the book.