not that interesting...
but what worked most was using kid's work to model and saying, "She could have said, ______, but she wrote, _____." I found that they just needed to hear lots and lots of examples of close-in endings and nonexamples so that they would know if they did it in their own writing.
Also, when we were doing that, I would be pretty forceful in asking kids to try new endings if they had ended with a far out ending. I find that with things like that, you kind of have to hold them accountable or they won't internalize it. For example, if a child has a three page watermelon story and I conference with them, I have them take out one page and grow it into a small moment instead of letting them think it is a real small moment.