One of the ways I make sure my Tai Chi postures are precise is to move along an imaginary line/s.
For example, when practicising the As If Closing Posture I think of imaginary lines extending from the palms of my hands. As I lean forward and push, my hands move along the extended horizontal imaginary lines and stop when I’m in the correct position.
The Tai Chi lines method can be used for any postures that have horizontal, vertical or angled lines. It just a matter of practicing one posture several times to determine where the lines are. Eventually, with enough practice, this line technique disappears and you will automatically flow through each posture seamlessly.
However, I do suggest that every now and again you use the line technique in case you have drifted from the correct movement of a posture; regardless of how experienced you are this can happen.
I’ve mentioned this line concept in a previous post Tai Chi: Line Alignment in regards to aligning the body when in a standing posture.
Imaginary circles and arcs can also be used to practice the Tai Chi postures for precision.
So try following the Tai Chi lines next time you practice and let me know how you go.