I'm a newbie, so I'm not sure if I can be of help or not, but I'll share what worked for us. First, anytime Fizz barked at our cats we would sit on the ground, lay a hand on her back and say the word 'calm' in a soothing tone.
If the barking was frenetic (such as when she became terrified of the toilet plunger) we would turn her around so that her back was facing the object and have her sit. We would repeat this as often as necessary until she calmed down. When she turned around again - there was no barking and she was no longer afraid of the plunger. Now she rarely barks and is very easy to calm down when she does. Good luck!
