I'm currently contemplating a possible new series. Yes, I know I have more to do on the Riviera first. I did say contemplating. It's legal, doesn't cost anything and it's fun. The messy part starts when you begin writing the stuff.
It's made me think about what constitutes a series. Obviously the books need to have something in common. On TV a series/serial can be installments of one story line, or possibly several, over a period of time. Or a group of characters appearing in each episode with a different story for each installment. The first would cover any of the soaps, the second detective dramas - same sleuth, different mystery. I think the first one might be a little more difficult to sustain in books in it's pure form, as the story would never complete, but lots of authors develop a plot line over a trilogy to good effect. The second option of course applies to numerous successful crime series in books or on the tele.
I've been thinking about other possibilities too. There might be a shared location - a village perhaps, with stories for different inhabitants. Lots of rom-coms are based on that sort of set up and the location becomes part of the attraction, and feels very real, like coming home to a familiar place.
The model I've been using for my Riviera Rogues is using broadly the same location - various places on the Italian and French Riviera - with a loose connection thorough the detective agency and a new couple each time. The idea that I'm mulling over, like many romantic suspense novels, would be based around an organisation. Crime fighting - good guys but not official. I'm not planning on researching police or any of the alphabet soup agencies. If I invent it, I can do as I like with it. My game, my rules - or probably theirs, once the characters start getting up off the page and giving me grief. I'm thinking interlocking partnerships and again a new couple for each book, and the chance of a glimpse at characters who have had, or will have their own stories.
I've done that a bit with the Rivera books - it's fun when you get an idea for including characters from other books in the current story. That's tended to be spontaneous; when I needed a Hollywood star it was natural that it would be Dan Howe from What Happens at Christmas.
This would be more organised and planned in the new idea. (Until the characters start doing their thing - see above) . So nice to have a plan - or think you have.
So- as I said, I'm contemplating. At the moment that's taking the form of wondering how all the different ideas I have, some of which are partially written, can be brought together. That's the fun bit.