It's easier to have someone else do it, I suppose.
The easiest and fairly painless method I know of which also doesn't leave a mess is carbon monoxide poisoning. Just make a charcoal fire in your bedroom, seal the room and go to bed. You're not going to wake up again. You have to take precautions of course to make sure no one barges in so you don't end up with brain damage in case you're rescued or kill the person that comes into a room filled with carbon monoxide.
