So then why do I botch endings so frequently?
On my two most recent books, I was very proud of both endings at first, but it turned out I whiffed them both. On one book, I ended it too soon. There was more to tell in the story, another page to turn. I had to go further to show how the events of the story really affected my main character. In the other, I was in a rush, so I pushed through, hit a dramatic scene, and typed "The End." It was anticlimactic.
What makes a great ending? I think maybe it's the sense that it's not an ending at all, but a new beginning. And this time, the character isn't encumbered by the conflict that was presented in the opening pages of the story. Sure, new conflicts might arise (sequels, perhaps), but rather than looking back over the bones of that story, the ending finds the character looking forward to a life free from the burden imposed by the original conflict. Hopefully wiser for what they've seen and done.
So I'm reworking an ending right now, and I'm trying to keep this in mind. But input is welcome ... what makes a great ending? How do you know when it's the right time to type "The End"?