As you go through a day, there are many occasions during which you block breathing by your posture or level of tension. Use this exercise to remind yourself to check your breathing and to remove factors that may be restricting your natural breathing.
Purchase some self-adhesive colored dots at a stationery store. Go through your house, your office, your car, your wallet, and your purse, and place these dots in prime locations. Each time you see one, use it as a cue to remind yourself to allow breathing.
Variation: Make signs (perhaps using sticky notes) that say things like breathe or wake up or remember and put them around where you are sure to be surprised by them regularly. Change your computer's screensaver so it says breathe. When you notice these reminders, attune to your breathing or lack of it. Allow it.
P.S. When people ask about the dots or the signs, use this as an opportunity to breathe again, and to spread the good word!