mangagirlpeach
ALWAYS include some sort of prophecy that predicts how everything must happen. Stick to the prophecy and don't let anything, be it character, situation, ANYTHING, interfere with The Prophecy because thats how prophecies work.
Especially those spe-shul "self-fulfilling prophecies;" no one will ever think, "Well s**t--I should probably ignore this advice", unless it tells them that they're about to die, in which case they should pretend they never heard it.
Kill NPCs often. They don't have feelings.
Actually, pull a Full Metal Alchemist and spend an entire chapter building up how special and adorable a child is, only to brutally mutilate them right after you're finished. (Is currently doing that in her new vampire story. sweatdrop )