It is important that the strength levels of these muscles be well-balanced and that each area is strengthened equally. You'll want to perform exercises that strengthen the muscles around the scapula, or shoulder blades. These muscles help retract your shoulders into proper postural alignment. Sitting at a computer all day tends to diminish the ability of these muscles to perform this task. Another area of focus involves the abdominals and back extensors.
Most individuals tend to do sit-ups or crunches for their abdominal exercise.
Unfortunately, few people perform the opposite motion and do back extension exercises. As a result, you consistently train your body in a forward bending motion but neglect to train it to stand upright as well. Back extension exercises, in which you lay on your stomach and attempt to pull your chest up off the floor, will help balance out your core muscles, help decrease low back pain and improve posture. There are also a variety of exercises that train your abdominals to hold your pelvis in it's neutral position during activity, called pelvic stabilization. This is an important role in preventing injury to the lower back.