Taking regular breaks. Whether it's a quick hourly stretch or a longer weekly break, stepping away from your activities can help you avoid burnout and stay on top of your game.
Surprisingly this improved my overall gameplay in competitive games. And I am not exhausted from work anymore.
Skill - an ability to do an activity or job well, especially because you have practised it
Seeing that almost nobody around me can take proper breaks because of all sorts of habitual factors it does seem like something you have to practise. Also, it's an activity of actively not focusing on a stressor is still an activity. (Debatable in a tricky zen master way I know, but are you actually a tricky zen master?)