Spend a few minutes, or even a hour or more, using your exercise ball in place of a chair or sofa. You use more muscles! I really enjoy doing this. I use an exercise ball (Swiss ball) while sitting at work, and at home, I'll deliberately pull the ball and use it to sit!
Simply pulling your stomach as you sit in a car or at a desk does a lot to burn calories and minimize your waist. One minute of doing so is equal to a belly crunch (per Denise Austin). I realized that when I was thin I did this all the time but somewhere along the way I lost this good habit. This is one exercise you can do and still get your other work done.
Bra fittings are essential. When my physical therapist suggested a posture bra for my back, I really didn't know where to begin. Many lingerie specialists offer bra fittings. Get one! The girls need all the support they can get!
Create a standing computer desk, or use an existing surface to compute and surf the net from a standing position. You will burn more calories, exercise posture muscles and, in general, promote better health than doing it sitting all the time.