What you need:
Concentration 
Paper 
Black Ink 
Darkness

This spell will not work if you don't really hate the person. This is black magic so be very careful. You must be in a dark place. Concentrate on your enemy for a few seconds, then take the paper and write the name of your enemy; cross it with a pentacle and chant:
"I hate you. I really do see your destruction suffer and leave this world once and for all."
Burn the paper and your enemy will die soon.