Engage your core muscles. Actively pull your navel toward your spine at all times and spread your shoulder blades outward from the spine to consciously activate the muscles of the upper back.
Knit your ribs. Draw your ribs inward to achieve a flattened chest, but roll the shoulders slightly backward to prevent the chest from caving in.
Square off your chest and shoulders. Even in arabesque, when one arm is extended forward, stay square by pulling the extended arm back into the shoulder. Reach forward from the fingertips to achieve a long line with your arm, but pull the top of the arm back into the shoulder joint to prevent your upper back from tilting off-center.
Work on the widest possible surface of your foot. If you are working flat, feel that your mid-sole is flush with the floor; avoid rolling inward toward your big toe or outward toward the baby toe. When rising on demi-pointe, the entire ball of your foot and all your toes should press into the floor. If dancing en pointe, ensure that the entire flat tip of the toe box makes contact with the floor.
Tuck your bottom beneath you. Avoid tilting your bottom backward as you bend your knees or rise onto your toes. Understand that you need to maintain your vertical axis even as your arms and legs move outward from your center.
Align your head and neck with your shoulders and press your shoulders downward. Keep your chin lifted and your gaze forward. Casting your eyes and chin downward can sometimes be enough to throw you off balance.