Have you taken her to any training classes? It might help to do short, pleasent, focused training routines when you have her near enough to a crowd but far enough away so that you still have her attention. Praise, treat and remove her from crowd proximity. Next time, see if you can approach a little closer but let her dictate what she's comfortable with. Clicker training works like a hot dang for this.
For the long term, giving her a job to do would be a huge confidence builder. What does she like to do? What is she good at? Agility-type stuff? Tracking-type stuff? Help her find her talents and develop them. Try her at as many different dog sports as you can. If there is something that she really enjoys, go with it!