You can always fill out the entire ballot with your preferences. That way you can be sure they will be distributed the way you want, rather than because of some deal done between the minor and major parties.
Apart from that you're stuck. If you read my explanation you can see that in a system that doesn't distribute preferences, if your candidate doesn't get in, your vote is essentially worthless after that.
The preferential system favours minor parties. I don't know why anyone would argue it doesn't.
If you don't want to express any preference after your first one, you can just vote as justis says and rely on the deals done by that party with the majors.
