I practice this with my girls every day. Even on the days I'm not with them we do this on the phone.
Every morning the conversation on the way to school or the bus is the same: "Tell me something good that will happen today."
Every afternoon or evening, the conversation is the same: "Tell me something good that happened to you today." Their morning answer and their afternoon answer are rarely the same.
And I found the one thing that both diffuses anger and makes my kids nuts all at the same time! When they are fighting or being mean, the one that was wrong has to 1) apologize and 2) tell the other something good about her.
I'm sorry I called you stupid. You aren't stupid. You read good books.
I'm sorry I smacked you upside the head. You dress very well and have pretty hair.
It's hard to stay annoyed when someone just complimented your hair. I try to practice this in my life as well. I apologize when I'm wrong (most of the time) and try to say something nice. Though, I think people would look at me weird if I told them they had pretty hair.
I think all said, I'm doing better with the perky thing than I thought. Now if I could just bust my own ass and post on a regular basis.