Perspective shift.
Imagine zooming out of your body, into the sky, looking down at all the people and land and everything.
You can't keep up with all that, right? But is most of it really worth much? Is a squirrel eating a nut over yonder really all that important?
Your attention is always limited in scope, but it's existing in a nearly unlimited world. So you have to manually constrain it with your own conscious decision-making. Goals are helpful in this.
Can also help to relieve the FOMO on actually genuinely important things to you by setting up a nice system that feeds you the news you want. There's lots of services.