Walk to some place quiet and at least somewhat open. Listen to the sounds your feet make on the walk. Listen to the echo off of things you pass. Walk slowly. Take slow, deep breaths in time with your walking, but don't let them become a struggle.
Close your eyes as you get close to where you will stand. Stop walking when you get there.
Face the east and remember what the twilight looks like as the sun sets behind you. Remember the dark filling westward until the night fills the sky. Imagine the light of sunset continuing behind you, away, around the globe until you can imagine the first glimmer of dawn to the east.
Turn to the north. Remember or find where the north star is, and imagine the stars rotating about it as the center point. Breathe deeply and imagine where the stars are during daylight.
Turn to the west and remember cool wind rushing at your face, driven by the receding heat of the setting sun. Let your mind coast with the sun, over the continent and ocean and continent again until you come back to where you are standing.
Turn to the south. Think of the sun rising and falling in the sky with the seasons. In the winter, the cold, hard light from low in the sky, and in summer, the penetrating heat from high. Remember the fall light, oblique and gentle. Remember the warming light of spring, new life bursting forth again.
Stretch upward, and remember that you stand on the ground.
Stretch downward, and remember that the sky is bigger than the earth, and it lies behind you, infinite.
Stand.
Breathe.
Open your eyes.