In an article at the Huffington Post, author Lev Raphael writes:
“Years ago, when I first met Walter Mosley, we talked about ways to keep a series from becoming routine for the author. He said his strategy was to take the series through historical changes, and see how they affected Easy Rawlins.”
He says, “In the Nick Hoffman series, Nick ages and is definitely changed by the deaths he encounters. His relationship with Stefan develops, too. Depicting a loving gay couple over time, and under stress, has been one of the joys of this series, whose books are now appearing as eBooks for a new audience.”
If you’re contemplating writing a fiction series, it could also be useful to plant some elements in the first book that will pay off later. For example, you might hint that a character is getting a bit too fond of drinking, which could turn into a full-blown issue one or two volumes later.
Another strategy series writers employ is to let minor characters in one volume become major characters in another.
Publishers like novel series and they have a big advantage for self-published authors, too: once readers like one, they’re likely to want more.
(For help writing your novel see “Your Creative Writing Masterclass,” published by Nicholas Brealey and available from Amazon and other book sellers.)