I'd like to be like that.
how do you do it?
Well tbh its mainly my personality and nature to be calm and unstressed,
but I would suggest to start to have a more positive outlook in life and to avoid constantly overthinking things.
Other things as well such as getting enough sleep ( Kinda tough with your work schedule), eating the right food ( actually works), and increasing physical activity ( Gets blood rushing to your head and helps you think clearly).