One of my greatest fears after finaling for a Rita was that I would not [ever] be able to write a book that wonderful again. Go ahead and laugh. All authors/artists are paranoid.
When I looked at my work schedule...which has kind of gone nuts...I realized that the best way to make sure I always write good books [hopefully, some great books] is to keep doing what I've been doing.
You all know I work with a lot of tools. Could/might/must and should list, storyboard, one-paragraph story summaries, lists of twenty. Those aren't just avenues to come up with better stories, they are failsafe mechanisms. Think about it...if I'm running my story ideas through four one-paragraph story summaries, testing them for strength, I'm probably going to continue to come up with strong stories. If I'm really thinking through my C/M/M and should list, then I'm going to find the best defining scenes for my stories. Using the list of twenty will result in cool, unique things: plot devices, humor, great things for characters to say and do. And the storyboard, ah, the storyboard, what better way is there to test the specifics of your plot? What better way is there to shuffle your scenes, test out the drama factor?
So I relaxed and told myself to chill. My next book or books might not final for a Rita, but I'll be proud of them.
My systems work for me. And so will yours. But the trick is, you actually have to have a system -- tools -- and use them. I know, the pantsers are groaning. But though you might have to ditch the storyboard, you can effectively use the list of twenty, C/M/M and should list and even the one-paragraph story summaries without spoiling your pantser fun.
When I was struggling with coming up with my third book, the great Alice Orr asked me, "How did you write your last one? Did you keep the synopsis you wrote from? Did you use a certain writing schedule? Did you play certain music? Did you mood write your scenes? What did you do?"
What did you do? When you wrote your last uber-successful book...What did you do?
Consistency is your friend. Doing the same things over and over, getting good at using the available pre-writing tools, rereading the how-to-write classics [like Donald Maass's books] get you into your writing groove. They create a creative anchor...something that tells your brain to get off its butt and work.
And if you want to be great [I know you do] the best way is to take your existing process and use it...gradually improving it as you get more experienced. :)