Recently I was having a discussion with a friend about choices. Why, she wondered, when I know I can try something different, do I feel better about what I'm doing? It's the sense that you have some control over your situation, I told her. When we have options, it's easier to cope with whatever we must do. It works the same way for kids. When you give a child choices that lead to the behavior you want, it's easier to guide the child to a good decision without argument. That's why, when getting ready for bed, for example, you can keep a toddler in relatively cooperative spirits by planning ahead a bit.
"Would you like to put on your jammies first, or brush your teeth and then jammies?" is one example. You can ask if they'd like a story while they're getting ready. This not only gives the child that choice, but offers a distraction. I'm a big fan of distracting children from overthinking onerous tasks like washing up. It doesn't have to be a formal story, you can just start with "Once there was an explorer fairy prince(ss) who had just eaten a delicious dinner and the Queen said it was time to wash hands, and what do you think happened?" All the while guiding the child through the process as you describe it.
As children grow older they can learn skills like this for themselves. Grade schoolers can be given a choice of which homework subject or chore to start first, when to take breaks and whether the break is five minutes or ten, and so on. Problem solve with older children to come up with ideas to help them develop coping skills and prevent frustration.
Just like having something to read while you're waiting at the doctor's office, or choosing when to take a short break at work; distraction, and choices that lead to good behavior are part of the self regulation skills that help us-- and our kids.