1. You need to be lagger. Its necessary to successfully cast magic.
2. R1 Spam with Gold Tracer will be great.
3. Bandit Knife help you with fishing Backstab.
4. The Main. If your opponent buffs or doing something else backstab him or cast Darkbead, it will be wonderfull. If he hurt you. heal. You have Estus, Humanity and Divine Blessing.
Good Luck!