Three pointers:
1. Pay closer attention to the kai/he, open and closed: by thinking of brushing your body with the closed arm ... it really is as close as that ... and also by thinking of always moving from the centre.
2. Pay close attention at the same time to the elbow of the open arm: it should always point downwards not outwards, in order to prevent the armpit being too chronically open.
3. Pay close attention to the legs: though you start learning with an exaggerated arch, this is only rarely held in such a way in more advanced practice, when the feet should be more closely parallel with the hips and the torso pointing straight forward. The legs should not be twisted or touching, but not excessively arched either. As long as the muscles are relaxed enough, it should still be possible to be loose in the lower back in this posture.
It is said that at a higher level Tai Ji, Ba Gua and Xing Yi become one: they are only different paths to the same goal, or different emphases.
