And never do it indoors.
Always suffocate. Knives and guns leave blood. Make sure you have a reason for your DNA to be in the room or wear a serious “white room” suit. Best to sink the body in water with weights. Never have an accomplice! Ever! A woman will get mad at you for some reason and turn your butt in and a guy will tell his woman and she will get mad at him for some reason. Either way your butt is grass. And make sure you are obeying every traffic law on the books when you are transporting the body or leaving the scene.
That being said, I am way too dumb to get away with murder.