I would want to work alone and would probably remain detached and wouldn't leave any kind of trail or calling card. I wouldn't be the kind of killer who needs fanfare [in fact, I would gladly allow someone else to claim credit for my work

.] If I took up such a hobby, it would be because I had a legitimate purpose in doing so; I'd be a vigilante of sorts, which means that I would lead a double life.
Perhaps, like, [MENTION=6164]Riva[/MENTION], I would go the snipper route, or maybe a pressure point induced heart attack or stroke. Possibly, I would use some centry removal techniques and simply snap their neck and walk away. Maybe I would iron palm the kidneys or the heart. Whatever method I chose it would be the most efficient and effective for the target and the situation.