The biggest problem that comes up in writing novels with a co-author is unrealistic expectations. We're people first and sometimes life, well . . . sucks. If one author's focus is on completing the book and the other author isn't on the same focus, it can get ugly. But one important thing that we adopted early on in our partnership was the "Primary author/secondary author" scenario, which removes that problem. There are a number of other co-authors that employ the same technique (such as Lincoln Child & Douglas Preston, who I read an interview about recently). One author, the primary, writes the WHOLE BOOK. Start to finish, with no help other than using the secondary author as a sounding board for ideas. The secondary author gets to go in when it's done, making wholesale changes at will. No red pen, no track changes. Just rewriting whole sections or chapters, or not. The primary author then gets it back, reads and and either accepts or rejects certain changes. Then it goes to the editor.
Having that sort of trust in a co-author relationship requires two things: 1) That you absolutely respect the other author's talent; and 2) That you can look past your own ego toward the betterment of the book. Because if you respect the other person's talent, you know the book will get better. And frankly, if you DON'T respect the other person's talent for creation and word choice, then why bother to enter into a partnership with them? I know that Cie is far better with characterization than I'll ever be. She creates real, living people that readers want to know. I know the book will be better for her subtle touches. But I write better action scenes and sex scenes (handy for romances!

) She looks forward to extra paragraphs that add the "Zow!" to those scenes. Between the two of us, the book is a stronger whole. But we've both been learning the techniques of the other during our ten years so now our individual works are as strong as the joint ones. Now the partnership is truly one of a coin flip because anymore, there isn't much to edit when we get the other's first draft. What does that mean for us and why keep doing it? Simple! Free money! We can produce twice the product in half the time and even when I'm not writing a book and am instead lounging in my easy chair with sore arms, I'm earning money because she's writing the next one.
Good times . . . good times.
