Following shoulder dislocation, what is the most important activity a person should do for therapy?

Rest: There is no specific exercise that will prevent a shoulder from dislocating again. It has more to do with the bony and ligamentous structures. However, scapular stabilizer strengthening (upper back) can place your shoulder in a better position overall.

Avoid Reinjury: http://www.theshouldercenter.com/unstable-shoulder.htm for more information. After an initial short period of rest, we typically recommend a detailed evaluation for patients over 40 years of age with a shoulder specialist because the risk for rotator cuff injury is also increased now in addition to the possibility of labrum injury.