Tree Pose / Vrksasana tells me about my state of balance and grounding before I am aware of it consciously (the body doesn't lie). I might think I feel okay, but my Tree Pose can be impossible to hold steady and I know then that, in fact, I am all over the place consciously as well… the body knows before the mind realises it.
This gives me the opportunity to be pro-active. To sit and ponder about the reason I feel unfocused and scattered. To be aware, not always needing or being able to change it, but to observe it and create the space for it. Being aware is already so helpful, so the state of being scattered doesn't hit you by surprise, and when you welcome it, it will change sooner or later for sure.
Tree Pose helps to focus and ground you
When standing on one leg it can help to image roots going down through that standing leg, as though you are as steady and grounded as a tree. Experience the lightness that comes from properly grounding, and stretch your upper body and spine up lightly to the sky.
Find stillness in the mind, keep your gaze steady on one point and try to keep your eyes steady too (not blinking the eyes) to support this stillness.
There are different variations of this pose. You can place your hands together in Anjali mudra in front of your heart or reach them up to the sky, either keeping them shoulder-width or touching the palms together. You could even try waving the arms gently, as if they were branches of a tree! You could also change the position of the leg, placing the foot on the inside of the thigh, ankle, calf or, if you're having a wobbly day, on the instep of the supporting foot.
A more advanced variation is to place the foot in a half lotus position, little toe side of the foot resting on the top of the thigh. You can even bend forward and place your fingers on the floor as you hold the position of the legs!