Firstly. to save yourselves a **** load of time, get yourself an ARTC certificate as an ELECTRICAL MECHANIC before you get to OZ.
This is virtually the same form as the TRA application which you will have sent in in the early stages of your visa application.
Getting the ARTC certificate is a very important step, as it will save you a lot of time if you need to work as soon as you get to OZ ( can take up to 3 months )
The only problem is you need an Australian address for the ARTC cert to be posted to. They wont post it overseas

so if you can, use a friends or family address.
Thats the easy bit done......
When your in Oz, you need to apply for a 'Permit to Work'
But first you must take a CPR (resuscitation) course, and get a Blue Card (site safety card)
Both these are compulsary, and you need to provide proof of both.
So, if your still with me

you can now work SUPERVISED on a permit to work (**** money too)
The next step is gaining your electrical licence.
This involves a college course im afraid. It covers all your basic theory ( volts drop, max demand, etc..) all the stuff you forgot years ago, and a practical test. ( 2391 comes in handy for this if youve got it )
There are several ways of doing the course, which you can chose the best to suit you at the local TAFE ( college ) they all take roughly 6 months and cost $1200 ish.
Its a lot to get your head round, think i started rambling half way through

If you need any help, i will do my best. Send me a PM.
Good Luck.
Sneaky