Start by making a list of behaviors your dog may have, observing your dogs actions or lack of actions under different circumstances.
This is an example; I left my dogs home to visit a neighbor, I came home to destruction, this was bad dog behavior to me.
Later I learned it was a mild case of Separation Anxiety Trust me at the time I did not consider it mild!
What you may learn is those behaviors you see may not be "bad dog behaviors" at all, but instead a natural progression of behaviors.
I will admit I had been a lazy dog owner, even though I felt I was loving them. They needed a "pack" leader.
Does your dog have a pack leader? Is it you?
Becoming Leader of the Pack
Start with "becoming alpha" every dog needs a leader to show him what is right or wrong, just as children do, otherwise they wander aimlessly with no direction and tend to become very insecure.
Establish that you are Alpha and each human member of your household is also Alpha.
It is important here to assure your dog that he indeed holds a secure position within your family "pack" (this is the bonding part).
Then on to Basic Obedience Training. Obedience training is a must for dogs, I found it especially true for Chihuahuas. Once you get the basics done, time to move on with the training.
Correcting Dog Behavior
You need to set your priorities, these were mine:
With my 6 dogs, each individuals, even though 4 are of the same breed; I needed help fast and lots of it. I looked for every resource to make our home run smoother, and not just be a canine training camp.