Aries: An ax or butcher knife is just fine, either one will do
Taurus: A brick, baseball bat, semi-truck
Gemini: A golf club or hiking accident
Cancer: Boat accident
Leo: Sniper
Virgo: Poisoned chocolates
Libra: Will get an Aries or Taurus partner to do it.
Scorpio: Victim died of unknown causes
Sagittarius: If you give this man a ride, sweet memory will die.
Capricorn: They are always plotting someone's demise already. If you know a Capricorn and they are angry at you, they are musing on ways to kill you.
Aquarius: Accidental death, carbon monoxide poisoning
Pisces: Are the best because you will never ever suspect them or see it coming. After all, they are naive, nice, pushovers and wishy-washy. There are plenty of old and unused homesteads in the woods that have old wells.
I am a Libra.