How to stop a dog from biting?!?!?

My 7 month old puppy(she is an aussie shepard and english springer spaniel) will not stop biting any kind of furniture and some parts of the wall from the house. We go to training classes and I have tired what they have told me to do but nothing seems to work. I have tired spraying bitter apple but my puppy loves the taste of it. My puppy loves to eat/drink pretty much anything we give her. What are some other solutions that we can do to prevent her from doing to bad behavior? Please help me!!