Firstly, in order to apply for solicitor you actually need to be Australian qualified. I am UK qualified solicitor and had to undertake additional study to become Australian qualified. You will need to pick the State in Australia you wish to immigrate and then undertake an assessment.
I don't want to deter you or be negative but I would say that 75 points is not enough unfortunately. I would however say look into the working holiday visa, go live there and make connections and look into the options for completing the necessary study to get a positive skills assessment.
Hope that helps a little