We have created Posture2, a series of exercises that makes use of a doorframe to help you develop and retain good posture. The doorframe works as a reference, a visual and tactile guide to increase body awareness.
You can also use the doorframe as a clue to remind you of your posture goals. I often stop for a few seconds during my chores to perform one or two of these exercises, just to help me realign my back during the day.
The doorframe exercises work well for people my size. Taller people may need to modify some of these exercises, reaching outside the frame for example, or they may need to find a bigger, non-standard door.
Our favorite workout on this series, the Overhead Slide, pictured here, stretches the trunk and the limbs as high as they will go, simultaneously strengthening the trunk muscles and solidifying what you have accomplished with the previous routines.