• Meditation is one way of getting control of your brain.

• Yoga and Tai Chi is a way of control your brain by focusing on your body.

• Recite a mantra is another way.

• Daily routines is also an auto-pilot way of getting control of your brain. (This one is good if you have trouble getting asleep(

You can train those methods consciously and understand the mechanics of how the controls work. Once understood and footpaths set (meditation, daily routines), you can switch between these controls if needed. Or force a thought reset (mantra)

It’s not a secret and known since ages. It’s just that people are too lazy to train. And may be prefer the comfortable auto-pilot way of living.