Biofeedback.. there's many ways an means to do it. The stimulus could be visual, hearing, touch etc. Visual- Use mirror. Hearing- just tell her.... My favourite has also been using sports tape to provide constant stimulus as a reminder for his/her posture throughout the day. For example- Hyperkyphotic, correct her posture a little by simply telling her. When that is done, immediately put a tape (preferably sports/kinesio tape) parallel to her spine from top (cervical or thoracic spine down to the lumbar spine At the back) IT WORKS nice with back exercises.