Once the decision says "go" then you enter the brain maze. If, in my case, you're writing a sequel then the characters (at least some of them) are already in print with developed foibles, personality traits, etc. but they aren't any more static than Joe or Jane on the street so new things have to be adhered to them and those things lie hidden inside the brain maze.
Larry McMurtry said that once he has a title ("Lonesome Dove") he can begin to write. His brain maze probably has a toll gate that requires the currency of a title. I can get behind that. I'm peeking and poking in my own maze for a title for the sequel to "Massacre at Fort Sage."
Even with some preliminary notes as to a direction for the story, the title still remains encased in a conundrum. Funny but the title for the book that this will be the sequel to was magically there before one word jumped onto the page. Ah, that this one would be that straightforward.
And the kicker is that this sequel has to take a backseat to a mystery that I'm finishing for a contest sponsored by Minotaur Books.
Interesting that the brain maze can allow you to wander in various paths some of which relate to the sequel, some to the other works that are suggested by friends, family and etheric happenstances. The maze is also a prompter suggesting things that have to be an amalgamation of experience, observation and craft. The maze is truly a work of magic.