Even though I do not have much experience in job placement for your field of work, I will try helping you based on my personnal experience.
It is pretty difficult to find a 'serious' job on a
working holiday visa, mostly because of the time constraint. With this visa, you can only work up to 6 months for the same company, which is usually a turnoff for many employers looking to fill permanent positions or longer contracts. The
working holiday visa is basically designed to allow you to work in order to finance your travelling and not to just let you work for a year. However, during my job search in
Australia, I did see many temporary posititons available in marketing and administration, so it would be possible to find short term work in your field. I think you just have to be clear about your motivations and ambitions for your trip to
Australia: are you going to explore the country and travel around, or do you just want to get some job experience overseas ? If the latter is your anwser, then maybe you can look at finding internship opportunities that you can set up before leaving.