I faced this challenge in Traitor's Moon . To accomplish this, I used multiple view point to introduce the various characters, letting their introspection, memory, and discussion with others to flesh out the situation. All this was important largely because the events of the new book were an outgrowth of what had come before. Continuity is important, says Flewelling. Readers resent mistakes, and will write you letters and ask you embarrassing questions at conventions and signings.
Continuity errors are sloppy.
Do whatever works best for you to avoid making them. I'm constantly referring back to old notes, and searching the books to see what final form an idea actually took after editing. The latter is very important, since things get changed and cut during the editorial phase, but after a few weeks or months, the author cannot recall every change made. You'd be surprised how much you forget, even though it's your own creation. These really bog a book down.