How do you stop dogs from barking?

I have a Jack Russell. Terriers love to bark. She is an indoor dog, so there is no barking at night.

I'm training her to keep her barking to a minimum. I keep a shaker can by the front door. It's a soda can with a few pennies in it. When she runs to the door to bark, I shake the can and give the "no bark" command.

It's worked fairly well. Sometimes I only have to say "do you want me to shake the can" and point to it and she will walk away.