What tips can I include in my work visa application for Australia if I work for myself?

Hi everyone, I’m going to apply for work dtv in Sydney Australia . I currently do work for another company but I operate under my own abn and submit my own invoices for payment. I’m just wondering if anyone has any tips or anything extra I can include with my application? I’ve got a copy of my abn registration, aswell as my certification for the role I’m contracting work for. Should I include copies of any invoices or remittance? Any other tips are appreciated, in a little worried as I don’t have an employer to certify a letter for me as I work for myself. Thanks in advance