If you're an author, my heart goes out to you. I feel for you in the fact that, each and every time you finish one manuscript, you have to come up with an idea for another. Once you have the idea, you have to develop new characters, a plotline, a setting, and decide which "person" you are going to write from. Some work on a deadline which can add to the pressure. You may have to do research of some type. Occasionally writer's block sets in which can result in several hours, even days, of total brain freeze. And, let's not even get into the subject of editing....
While I don't mean to brag, I think I may have the upper hand by being a series writer. Each book in the Forever Love Series ends with a cliffhanger which serves a two-fold purpose: 1)it makes the reader eager for the next book in order to find out what happens (a clever marketing strategy!); and 2)it gives me the idea to work from for the next book. Because one book feeds off the plotline of the one prior, the characters remain the same. I need only to add one or two new ones per book to keep it all interesting, and that's only if I feel they will somehow be relevant to the overall theme. I use a James Patterson Women's Murder Club series style of both first and third person, so all the stories are told from the same POV. (and hey, if it works for him....) Being self-published eliminates the deadline issue, so that just leaves editing. Once again, we won't talk about that.
So, now that I have a third book in the making, I should be sitting pretty. Right? Not exactly. While being a series writer does have advantages, it comes with its own set of challenges that "individual" storytellers may not face. One of the biggest issues I deal with is to make sure my novels aren't clones of one another. For me, it's all about taking that cliffhanger ending and using it to build new, exciting, and entertaining circumstances for my characters to encounter. Its about being careful not to exactly duplicate scenes from the previous books even though my characters may find themselves visiting the same places or talking to the same people. I have to incorporate just the right amount of backstory into each book so that readers will be reminded of who someone is or why something is happening. Backstory also serves as a method to provide pertinent information to those who may not have followed the series from the beginning. Then there's always the task--once I get through everything else--in creating yet another cliffhanger ending that will be interesting enough to entice my readers into wanting the next book. After all that comes the tweaking, revising, more tweaking, rewriting, and yes, editing. Oh, and by the way, I'm not exempt from writer's block, either. There are many times when my muse decides to take a hiatus.
So, what's my point in all this? The point is that we as authors all seem to face the same obstacles in our writing regardless if we write all our novels individually or string them along as parts of a series. We all have those day-to-day issues that we strive to overcome in order to deliver that fresh manuscript to the publisher on time. The good news is, we do it not because we have to--after all, no one is holding a gun to our heads to make us write. We do it because it's in our blood. It's what we live for. And when we hold that finished product in our hands, that completed manuscript or published novel, we know it was worth it.