There's always a time lag between sending back a signed contract and waiting for the editor's letter detailing the changes she feels will improve the story. I continue work on my current project but I know her letter will turn up and I'll have to redirect my focus. Switching to another set of characters can be hard, getting back into the rhythm and world of the other book is often jarring when my thoughts have been consumed by the present crew.
But it does feel like meeting old friends when I dip into the manuscript and begin to immerse myself in their problems once more. I know these people and I know how they think. My editor's instincts and insights are mostly things I agree with and she rarely wants major changes. Sometimes we have a discussion on Aussie vs US language. For two countries using the same basic language there are a surprisingly large number of words and phrases that differ.
When the revisions are finished it's time to go back to the current work in progress and reacquaint myself with the characters waiting patiently for me to continue their lives. A few months later a big parcel will arrive with the A4 printed pages of the novel for a final read through for errors. Again I drag myself away from the current story and plunge into the previous one for the last time. The next time these people will appear in my life they'll be in their shiny new book with another lovely Avalon cover.
Look out in 2012 for Dimity and Marcus in Love On the North Shore Line.