Some punch-list items for baseline standing practice to open the body common across multiple methodologies:
- Suspended crown of head as a component of opening the body upward (intent drawing upward beyond the physical confines of the body) -- complemented by . . .
- Letting the hara/dantien settle (intent drawing downward beyond the physical confines of the body), establishes fundamental up-and-down / yin-and-yang opening of the body -- further complemented by . . .
- Opening the body using intent in opposite directions along the two remaining axes (i.e. six directions) -- and in the process being sure to . . .
- Keep juncture points throughout the body (e.g. underside of chin, armpits, arch between the legs, spaces between fingers) open and radiused, vs. closed and pinched -- while maintaining . . .
- Shoulders relaxed and integral to the torso -- which helps ensure . . .
- Hands connected to the ground/feet via and filled from the center (intent drawing into and beyond the hands).
Again, the internet is a poor medium for transmitting the details of this topic, and the English language in particular is poorly suited to conveying the nuances within those details. With those limitations in mind, if someone simply says the above is "how to stand in six directions", while someone else observes "based on the punch list, arcane notions of alignment and structure are integral to standing in six directions", then down comes the "APPROVED" hanko in either case.
But, like Hugh said, you have to know what it's supposed to feel like, and that takes us back to hands-on to initially, and ongoing, refine that understanding.