Look around you to find representations of ideal posture. Very young children will often move their bodies in more optimal ways. Look at the relationship of the head to the spine in a child who has not begun to imitate others who slouch. When you walk down the street find reminders amongst the people you observe of ideal ways to stand and move. Practice them there and then by taking on their gestures and movements. Find masters and role models, or work with a Spacial Dynamics® practitioner to help you stay motivated and learn to change.
The more we find ideals the more our habit body is softened and ready to change. Become a work in progress!