You should practice @ least once a day, preferably when you are relaxed, so when anxiety hits you'll be ready. The divided breath has 3 parts to each inhale and each exhale. Imagine that your lungs are divided into thirds. Top third, middle, and bottom third. On the inhale imagine filling the top third first, take one second pause, then fill the middle, a one second pause, then the bottom third. Exhale in the same manner, but in reverse. As you get better at this increase the pause to two or three seconds if possible. When I first started this practice I could not even pause at all, so don't be discouraged-it takes practice. The main idea behind this is to learn belly breathing, and discouraged hyperventilation. (I used to over-breathe without even being aware of it and got some pretty bad physical side effects!) When you shallow-breathe/hyperventilate you are actually changing the ph of your blood, which then gets pumped around to all of your systems, making all of your anxiety symptoms worse
I hope that you find this helpful, it really worked for me
Good luck!
Scaredy Cat