Counting to ten helps me, but any amount of numbers works. Sometimes I count all the way up to 100. I also like counting sheep and if that gets boring, I picture a sheep fashion show and put them in different clothing as they jump over a fence and do other 'normal' sheep things. That and other visualizations I keep close in my mind, so that I may relax my mind a little. I am not sure how much of rational thought this is or if it helps when battling irrational thoughts, but they act almost like a security blanket, which is comforting