working backwards

I had a long talk with a friend yesterday, mostly on writing topics. I have a project that I love the idea of, but so far the execution hasn't gone all that well. My kids (who are very honest) read it and tell me that they like parts of it, but the ending is all wrong. I know this, since I've reworked the ending about five times completely. But talking to my friend made me think about how to fix the problem.

I tend to work at books chapter by chapter. I don't say that as a piece of advice...