It’s not easy keeping track of details in a novel that goes back and forth in time. Or any book of fiction, for that matter. What do I mean by details?
Details relative to the characters could mean simple and obvious characteristics such as eye and hair color, height, weight and age, gender, dress style, likes and dislikes, personality quirks, language and speech mannerisms. Believe it or not, it’s not always easy to remember all of these unless your characters re-appear in several books. I keep a list of all these traits for each of my characters. In fact, for each book that my main characters appear, I re-visit the list to make sure I’ve aged them appropriately. Even a year off will throw your readers into a tizzy.
More important, when dealing with generations of families, or when you go back in history to another time period, chart your way through the years, decades, or centuries involved. Ancestry maps can be helpful.
My current work in progress goes back to World War II with the “grandparents.” In modern time, the “parents” and “grandchildren” are featured. It’s vital to have all those years mapped out. How old were the grandparents in the 1940s? How old are the parents now? The grandchildren? When did they marry? Who did they marry? Trust me, it’s confusing if you just wing it. Your reader will definitely notice that the parents could not possibly have been born if the grandparents were already dead.
Another detail to be meticulous about and I must say I have been remiss in an early book, is language and speech. If a character is from Boston, don’t give him a Brooklyn accent or use an expression that is idiomatic to the wrong region. Same goes for dialect, and, by the way, don’t use too much of it. It’s distracting.
If you use foreign language phrases, please, please, make them correct. A Google translation will give you the basic words, but is the phrasing correct? Do the French, Germans, Slavs, Poles, speak like that? Make it authentic. Ask someone who speaks the language.
It takes time to get the details correct, but in the end, your work will be far more authentic. And your reader will thank you for it.