Wave Gazing
Find a place where you can sit and see the water without distraction. A beach, a pier, a headland.
Sit. Look at the waves.
That's the whole practice.
If you want instruction: don't try to follow any specific wave. Don't try to clear your mind. Don't count. Just look. When you notice you've stopped looking — you're planning dinner, reviewing a conversation, whatever — return your attention to the water.
Do this for ten minutes. The first two will be restless. The middle six will be peaceful. The last two will feel like the world has slowed down.
Researchers have measured this. Fractal patterns like breaking waves, flickering fire, and leaves in wind drop alpha wave activity in specific frequencies associated with stress. You don't need to know the science to use the effect. You just need to sit by water.