"What happens when my dog gets it right?"
I use a variety of rewards and reinforcement strategies depending on the dog. Generally food is the fastest way to get new behaviors. For two of my dogs the all-mighty ball is their biggest reward. Some dogs the opportunity to sniff and explore is a huge reward. All that matters is that the dog wants it and I am smart enough to figure out how to use it.
"What happens when my dog gets it wrong?"
Generally, nothing. A big part of initial training is to set the dog up for success. This means that I don't often let them be wrong. If I am asking the dog to do something and they respond in a way I don't expect I try to figure out where I went wrong. Am I too close to a distraction? Have I worked with my dog on what I'm asking recently? Did I maybe move too quickly and skip a step? I take full responsibility for my dog's behavior, I'm supposed to be the smart one in our relationship.
"Is there a less stressful way to do it?"
Maybe. I know that I am a better trainer than I was even one year ago. I am always learning new methods and new ways to approach changing behavior. My goal is always success with as much fun as possible. I want my students to be excited to come to their training classes. I want it to be the highlight of their dog's week. Some training is stressful in small increments because life is stressful and our dogs need to learn how to tolerate stress to a degree. Ultimately what matter most to me is the relationship we're building between owner and dog. A well trained dog is just a by-product of a great relationship.