Strengthen your body's core muscles with yoga, Pilates and other calisthenics. Achieving balance while ballet dancing is not much different than achieving balance in any physical task. Good balance requires a strong core. Do exercises that strengthen your back muscles, abdominal muscles and side muscles regularly.
Practice holding position in front of a mirror until it feels natural. Regardless of the position that you're practicing, hold your body up and out from your hips instead of settling down into them and allowing them to hold your weight. Keep your shoulders wide and apart, lift your chin and lift your ribcage up and out.
Strengthen your ankle and leg muscles using plie. Dancing en pointe requires immense ankle strength to hold your body upright. Practice plie (bending of knees) often, focusing as you lift your body from from the flat foot position to a releve position (raising the body on pointe).
Close your eyes while practicing on the barre (stationary handrail). You often use sight to maintain your balance, but when you're moving rapidly, as you do in ballet, you can’t rely on sight alone. When practicing ballet on the barre, close your eyes and complete a few steps until you feel confident that you can maintain your balance.
Improve your upper body strength through calisthenics. The upper body is incredibly important for maintaining balance. This concept is illustrated by the tightrope walker who uses a pole to balance on the wire. The same concept applies to your body.
Focus your mind by practicing exercises that improve your concentration. The mind is just as important for maintaing balance as the body is. Giving in to distractions or allowing your mind to wander can throw you off balance just as quickly as losing your equilibrium. Pull your mind back to the task while practicing ballet over and over until it becomes natural.
Stretch your muscles. Keeping your muscles warmed and conditioned goes a long way toward helping maintain your balance because it allows your muscles to operate at their peak ability.