Well, she gives me an objective opinion about the issues I struggle with. What sometimes feels catastrophic for me isn't necessarily so from an outsider's point of view. Left on our own to ruminate about our faults or flaws, it's really hard to see that we're much better off than we realize. And it's hard to recognize your own negative thought patterns over time -- I might be able to realize when I'm having a negative thought, but the *pattern* is something hard for me to see.
A good T should be able to guide you as to the "how" to increase your self-esteem. I know this isn't the specific answer you might be looking for, but I do wish you the best of luck