Correction of excessive barking takes perseverance. Keep using the command "No bark". When she stops reward her with a very enthusiastic "Good Dog". You might want to actually gently hold her muzzle so she can't bark as you say "No bark". She needs to understand the command first and then obey it.

I'm also a big advocate of checking out a lot of dog training books from the library. Different dog trainers frequently use different methods and you might find one that is the one that is best for you.

If this barking is occuring outside, I would bring her into the house as soon as she starts barking where you can control the behavior.