How do i get my puppy to stop barking on walks?

My puppy is now 9 1/2 months old. She is a "rat-chi-weenie", one parent chihuahua and dachshund and the other parent chihuahua and rat terrier. I know people say little dogs bark but this one is out of control, I don't mind her barking instinctively when she hears noises at night or even when she's playing. Her barking is making it impossible to walk her as it is rather embarring as it is excessive. We have 1 other dog so I have an idea of what's excessive, as well as just watching other dogs.. She barks at every animal, person, car, she even seems to bark when she's walking or running just to bark. Any suggestions?