I just had my DTV (workcation) approved from Canberra, Australian Embassy.
Applied July 1st, asked for more documentation (proof of being able to work overseas) on the 4th and approval came through last night (30th of July).
A few things I've seen people ask about:
I had a sponsorship letter from my parents
I am a freelancer and wrote a letter on behalf of myself with my own company letterhead.
There was some good advice in this FB page, so thank you!