Source: http://www.willamette.edu/~jlaronge/principles.html

1.Straightening the head.
Stand straight, relax your neck and suspend the head naturally erect from the crown point without strain or tension. The image to model is "hanging by a string from the top of one's head" such that the head and neck align by the force of gravity alone.

2. Correct position of chest and back.
The chest is kept slightly depressed inward which helps enables one's breath to sink to the lower belly. The upper back is slightly bowed outward while the pelvis is tucked under.

3. Remain relaxed with no tension.
Relax and loosen all the joints, particularly the shoulders and elbows, and sink them so that they are flexible, connected and are able to integrate into proper structure. Relaxed does not mean limp. Proper structure is held with a minimum of muscular exertion with gravity providing the downward stacking, providing power from the root into the ground. transfers energy in the form of a vibration much like a whip which has no tension. When the musculature and joints are relaxed, aligned, and connected the wave or pulse of the movement is conducted through them with no retained tension.

4. All movement comes from the center.
The waist is the "ruler." All movement comes from the waist, whether it is a hand movement or a step. Make the waist cause each movement . The waist as the "ruler" must be relaxed, initiating, controlling, guiding and distributing the direction and amount of energy transmitted.

5. Harmonize the upper and lower parts of the body.
The vibration of any movement roots at the feet, releases from the legs, is controlled by the waist, moving eventually through the back and arms and finally is expressed by the fingers. To achieve this coordinated path first requires that the feet are at all times firmly attached to the ground like big roots of a tree. The knees must remain slightly flexed. Finally, the upper and lower body must move harmoniously so that all parts of the body are strung together without the slightest break.

6. The entire body moves as a single unit.
The entire body should move as one complete unit, not just a hand, leg or arm. Once one part of your body moves, every other part of your body should also be in motion; when you are still, everything should be in stillness. "Be still as a mountain...move like a great river."

7. All movements are performed in a smooth manner, with no unevenness, and continuous, allowing no interruptions.
All movements are performed smoothly and evenly. This means that the movements in training never speed up and then slow down. There is never a detectable start and finish from one form to the next. A common image used is that of reeling silk thread from a cocoon. Reeling too fast or suddenly will break the silk while reeling too slow or in the wrong direction may tangle it.

8. Maintain the clear distinction between substantial and insubstantial.
Agility is the result of non-double weighting. This means that one's weight is never maintained equally over both legs. One leg is always heavy and one leg is light. By only maintaining one point of substantial contact with the ground you gain the ability to move quickly, much like a ball which moves easily across the ground because it only has one point of contact with it.

9. Breath deeply from your lower belly and in harmony with the movements.
The breath is deep and full, filling oneself from Tan tien (2-3 inches below your navel.) Each movement is linked precisely with the breath, so that as one expands the body, there is an exhale, and when one contracts the body, there is a inhale. Since the breath is linked to very slow movements, your breathing will also be very slow.

10. The mind leads the body.
In , one focuses the attention on the mind, instead of on force. Therefore, use your mind to direct your movements, and let the body follow. Keep the mind fully conscious, aware, and with intent along each and every tiny point along the path of the movement and each point of the body. The mind and breath are king and queen and the bones and muscles are the court.