Moving slowly should always be done every step of the way. It can never be overemphasized because the slow smoothness of your motions will improve the connection of your body and your environment.
Never let anything disconnect you. You should always stay connected with every instruction. If you have been disconnected, continue to perform the movements and listen carefully to the instructions so that you can overcome any distraction.
Your knees must always be bent during the entire form. Your height must not bob down and up. There are some considerations but all the while, your height must always be maintained at a level that is constant.
The power of Tai Chi travels differently from the movement of Tai Chi. Power of Tai Chi will start from the feet going up to the legs, controlling the shoulders, and will be expressed by the fingers and hands.
Your head must be maintained as if it was suspended on air.
Your chest must be depressed and your back should be raised but this must be done without exerting any force.
Your breath must be focused on your dan-tien but force must not be exerted. As time in the program may pass, there will be accomplishments that will fulfill you like synchronizing your breathing with the movements that you make.