How you move and use your body in everyday life will radically affect your progress in tai chi chuan and baguazhang.

Day-to-day habit patterns are the strongest.
These are the hardest to lose.
If you spend all day hunched-over, tensing-up, nervous, over-extending... this cannot be ironed out with a 90 minute class.

It is necessary to think about body usage as you are using it.
If you catch yourself off-balance, strained, tensing - then stop.
Re-establish equilibrium and perform the task again, with mindfulness.

This may sound a little difficult, and it is, but with practice you will improve very quickly.
As new habit patterns emerge and you begin to move as a unified whole, disconnection will be immediately evident and feel physically uncomfortable.