She is old enough to try hypnotherapy. This can address anxiety, social awkwardness, shyness, low self esteem etc.
It may be hard for her to listen to what you've got to say because she may be interpreting it as criticism. If the CBT had worked for her, you may revisit that option if there is group counseling offered in your area for her age range.
You can encourage her to get involved in activities that bring her a sense of accomplishment and improve her self esteem. She may be introverted hence preferring one friend versus a group of friends. Talk to her about dependence and that giving others a chance is also letting others know her better as a person. If possible, see if she will share what is causing her behavior (which is usually purposeful) Encourage her to journal and use workbooks if she finds it hard to talk to you. She may agree to let you see what she writes.
Hypnosis for Self-confidence and Self-esteem (Hypnotic Empowerment Series for Self-Awakening) (Hypnotic Empowerment Series for Self-Awakening) by Janet I. Decker (Audio CD - May 17, 2007)
Teen Esteem: A Self-Direction Manual for Young Adults - Paperback (Jan. 1, 2010) by Pat Palmer and Melissa Alberti Froehner