"Ideas are easy, writing is hard."  How do you choose which ideas are worth pursuing?  How do you decide when an idea just isn't working and move on to something else?  What if you've already taken an advance?

You've scored a book contract with a major publisher, but they want changes.  Editors can't always be right, can they?  Is there a 'line in the sand' you just won't cross?

It's hard to keep track of everything during an epic battle; what are some strategies to keep things under control?