The most important thing is to take an appropriate anti-emetic and no eating shortly before attempt.
My favorite cautionary tale on this concerns the suicide of Lupe Velez. In the "official" Hollywood version, she ate dinner with friends, took Seconal with alcohol, and later "died peacefully in her satin bed." But I prefer the more probable version (from the tell-all "Hollywood Babylon") that reflects what really happened before the old Hollywood system cleaned up the "official version." She had spicy Mexican food with friends (no empty stomach), took no anti-emetics, and when she started to vomit, went into her bathroom, slipped on the floor, her head went into the toilet, and she drowned.
I think of this every time someone contemplates the "do I need an AE?, do I need to fast?" method. Well sure, hopefully, you want your death to be dignified.