Dear Bijou Drains,
If you have never trained a dog, most training books of newer vintage will be helpful.
You may have noticed an antagonistic tendency in the responses to your innocent OP. This is because there is currently a difference of opinion among dog trainers (in some cases causing screaming in fury and worse) about methods and philosophies.
In a nutshell: it turns out that praise and dog treats when applied with correct timing go a very long way in teaching a dog concepts that are otherwise rather meaningless to the dog, like sitting on command, staying out of the kitchen, dancing on its hind legs, etc. “Correction” aka harsh words or forcible actions, inhibits learning these things. A clicker or other simple fast noise (like “yes!”) is just a way of marking the wanted behavior. There is no particular magic to it but it is helpful.
This method has become a kind of moral philosophy for some dog trainers, and called “Positive Reinforcement”, a misunderstanding of behavioral modification terminology.
Cesar Milan is not a dog trainer per se. Copying what he does can be a big mistake if you don’t understand that dogs respond to him because of his centeredness, experience, awareness and personal power aura, not because he makes some specific move.
One thing he emphasizes which will be very important for your particular breed is that dogs have a hard time behaving well if they don’t get enough exercise. For an Aussie, that is a LOT of exercise. Today my 2 year old Aussie ran off leash for two and a half hours in the forest meanwhile fetching a thrown stick at a dead run, about every 3 minutes. The last throw was fetched at the same dead run as the first one. She was not tired out. At all. My 8 and 11 year old Aussies were happy to lounge about afterwards though.
Fact is, Aussies are one of the quicker-on-the-uptake breeds and also tend to want to work with you and please you. An important thing to remember is that whatever method you use, an Aussie will either make progress quite rapidly, or you are doing something wrong and need to change your approach.
Classes can be great or crappy, depending on the teacher, and on some degree, the other students and their dogs. After your dog knows how to heel, sit, lie down, and stay at home, that is a good time to take her to a class, to teach her to do those things with the distraction of a lot of dogs and in a strange place – it’s called ‘proofing’, an important part of training.