By keeping your chin parallel to the ground, it means your spotting will be as efficient as possible. Having a lifted chin or a chin that is too low, will throw off your alignment. It can also impact where your gaze is when you are spotting which could also throw you off.
In your preparation, push down into the ground through the balls of both feet. When you spring on to your supporting leg, continue to think of pushing down into the ground with your supporting leg while lifting up with the hips and the lower back.
Arms are essential to finding a great balance. Make sure that they too are parallel to the floor if arms are in first. Make sure the arms display the correct position and are being lifted from the back rather than the shoulders.
Pro-tip: Take a slow-motion video to really understand what your positioning is in your turn.
Lifting the passe may be the key for getting in that one extra turn. As your turning, focus your thoughts into raising that passe just a tad more and to dedicating more energy to the turnout.
Pro-tip: Practice lifting the passe while balancing at the barre. Alternate between lifting and then relaxing.