SW, my baby sister suffered from nightmares and would crawl into bed with me wimpering in fear. I was just a kid myself, but this worked for me.
We had recently seen Cinderella (first time showing in the theatre) so there were very good moments that we liked. I told my baby sis to just think about the three little faerie seamstresses and to pick the one she wanted to be. "Dream about singing to Cinderella and making that beautiful dress..."
It worked and to this day she uses that sort of dream control. As silly as it sounds, I do the same when I am overly stressed.
Edit: Obviously, my example needs a 50 year update to be relevant.
