Lol there's a lot of options....... Are there certain things you won't do or that appeal to you? If you imagine you can climb over an overpass to off yourself, maybe jumping off a bridge would work. If you have a means of transportation, just pick one; society would prefer one that isn't over a populated space.
To suppress the survival instinct, I would recommend conviction and preparation. Even if you feel fear in the moment, if you know beyond a shadow of a doubt that what you're doing is right, there's no rational reason not to do it, hopefully that can power you through irrational instinct. And if you lack this conviction, you probably aren't ready to kill yourself