This asana is difficult to maintain balance not only while in the posture, but also on the way into and out of the posture.
Pelvic stability and use of the core strength will be key to maintaining balance.
Basics of any standing postures
1. connect the front foot and the back foot to press each other, as you tuck the legs into the hips firmly and keep the hips stable, so it is counterbalanced and the posture should be more stable and more deepened.
2. Try to shift the weight onto the back leg as much as possible.
3. the tail bone, the spine, the neck and the head should be aligned and lengthened.
4. Engage the psoas.
As you follow the basics
1. Separate the feet a leg width apart, keep the front foot pointing straight ahead, turn the back toe inward at 45 degrees agaist the front foot, and align the back heel with the front foot.
2. The front leg is adducted and externally rotated, the back leg is adducted and externally rotated.
2. Keep the hips squere. keep the weight on the strong back leg as much as possible.
3. Twist the waist to focus on the longest center line of the body as the central axis.
4. The arm reaching for the ceiling is abducted and external rotated, the arm to the floor is adducted and rotated externally.
5. Look at the hand reaching for the ceiling.