Happy place happy place happy place....Haha. That entire run I was picturing myself explaining what I was doing to the crowd, even moving my lips a little but not actually talking, because my happy place is speaking in front of people and performing. I talk to Selena a lot during the barrel races because it calms me down. One of the girls on my team tells me she pictures herself on a trail ride. She pretends the judges aren't there.
Also singing and talking relaxes your body and makes you breathe. The reason horses get tense when we do is because we subconsciously breathe shallower or take fewer breaths and stop moving with them. If you keep talking or singing you have to breathe, and singing is fun. :) It flows right down through your seat to the horse.
Another thing is just little confidence boosting things. Focus lesson schooling your horse and more on just playing. My trainer had me and Selena in a group lesson doing drill team maneuvers. She had six of us there and this was when I was still nervous with my horse and she made me run and turn and keep up with my lesson mates. She played music and it was a blast because I didn't have time to think about Selena bucking or rearing or taking off, I just had to think about where I had to be and that made me ride like I actually wanted to go somewhere. It was a huge confidence booster for me. Playing games helps too, like horse soccer or musical ribbons (Like musical chairs but with ribbons tied to the arena rails), the dollar bill race, flags (Like run and pick up a flag or dropping flags in buckets), anything really that makes you focus on a job instead of your horse doing stupid things.