Get out there and knock on doors mate, that's how most of us do it and it works if you approach it correctly. You might just be surprised at how many will say yes, I know I was. I moved to the country last year and I have around 14-15 properties now and I get offered them all the time these days.
It's just a matter of as I said approaching the subject with some common sense and striking up a conversation with them and eventually letting them know your interested in shooting (in my case I start talking about foxes) and I will ask them if they are having issues with foxes etc and if at all possible that I could come and whistle a few around their property, quite often they will say if you're interested you can shoot a few around here for me
Don't go carting the dogs around with you etc, just go on your own for a drive and if you see a farmer in a paddock pull over and have a chat, I've done that quite a few times and most times I will end up with a property to shoot on out of it. (Picked up one a few mths back by doing just that, saw a fella working in a paddock putting in a new gateway, mentioned what I was up to and he said if you'd like you can come and shoot a few foxes here too!
I took his details and have been out a few times now poking around for foxes (took all of 5mins to get another property).
I now get farmers recommending me to other farmers and a few months back I picked up 4 properties in one hit because a farmer recommended me to another farmer and that farmer put me onto his neighbour too!
Also don't go rolling up in camo looking like some full retard mall ninja - just wear your everyday type clothes etc - just get out and talk to people you will see.
My mate was telling me today how he picked up a property - he was sitting on the side of the quiet country road having a cuppa and throwing the ball to his kelpie when a couple of cars came past, a few mins later a farmer drove up to see what he was upto, anyway it turns out the farmer thought my mate was a illegal pig hunter (apparently this fellas had trouble with them cutting his fences etc) anyway my mate explains what he's upto and the mentions he likes hunting foxes - ol mate said your welcome to come and shoot afew around here if you like! 11,000 hectares later my mate has yet again another property to shoot on.
I've done the same sort of thing, been driving out to a property to shoot foxes, saw a farmer on his motorbike approaching and pulled up to let him pass, he stopped to say thanks and G'day and I got talking to him and mentioned I was heading to a property up the road to shoot some foxes etc and he said ya welcome to shoot on mine too if you want too, I took his details etc and picked up a heap of land adjoining the property I regularly shoot on!
It's that easy if you bother to try.
Good luck and happy property hunting.