Death spells

Nice to see some curses being discussed :) As mentioned in previous posts, it shouldn't comeback at you 3 fold if you don't subscribe to that school of thought.
Though if you are concerned then you could cast a protective aura over yourself.
Note that when casting a curse it is fairly normal to feel a little of the energy after casting, all it means is that you didn't push all the energy to your target. Nothing to worry about really.
I'd advise you create you own curse appose to asking for an existing ritual, that way you can tailor it to your preferred methods.
When deciding on what to do bear this in mind:
Your target should be open to magical assault before casting ( perhaps feed of their energy to wear them down)
You must have your intention very clear, any doubt or uncertainty will weaken the spell
Think about how it will manifest, you will see better results if you push for a specific illness or accident than if you just generally wish death on them.