Did you go through the Notes & Resources section? I believe there are a number of existing resources and other relevant material that would assist you with this:
Full notes covering entire SOR 1 course with Christianity and Islam as the Depth studies. The Christianity section only has essay plans. Got a HSC mark of 46/50 with these.
boredofstudies.org
I have also uploaded a depth study on Christianity to the Notes & Resources section:
Useful as a guide towards completing your depth studies and/or as notes to supplement your studies and preparations. Do not plagiarise. All the best with Studies of Religion! 😄