1. A relatively surefire method
Meaning it has to kill you, not leave you to suffer, damaged and sentient in some hospital room, unable to finish what you started without help. They say that you need to jump off something really high to be certain, that that’s the closest to surefire you will ever get.
2. A method that is psychologically appealing
Meaning that you can see yourself following through on. For example: lots of people can’t stand the sight of blood so the thought of cutting wrists turns their stomachs.
Seeing that there is usually no coming back from this, this is not for those who are dithering or tremulous on any level. If you have to think about it you probably are not ready. There can be no questions anywhere in your mind.
4. No one you care about leaving behind
This has to be selfish and completely private by definition. If at any point anybody else other than you crosses your mind you probably are not ready. You have to be fixated and obsessed and completely single-minded about it.
5. No opportunity for last-minute regret
In the first point in the list I pointed out the fact that with jumping off high places there is the issue of a long fall to the ground. You get to think and feel regret after you have gone past the point of no return. It is but a few moments, but there is time for conscious, pointless remorse which is not how you want to spend your last few moments. With hanging or sleeping pills or anything that takes time there is this issue. You want to opt for the kind that takes you consciousness immediately after you have made the final step.