Echo of Sylvanas Stay out of purple stuff on the ground. When phase 2 comes, kill the ghoul everyone's DPSing and then run over its corpse and away from Sylvanas.
Echo of Tyrande Interrupt Stardust and blow your cooldowns at 30%. If you're ranged, don't get close to her, and if she turns to face you, move away.
Echo of Jaina Avoid big white blades that pop out of the ground. If you see a fire ember on the ground, stand IN it to keep it from damaging the whole group.
Echo of Baine Throw his totems back at him. If he stomps an island that you're on, swim to a new one quickly.
Murozond Stay out of big golden circles, stay out from in front of him, stay away from behind him, and pop your cooldowns whenever time resets.
Well of Eternity
Peroth'arn Stay out of green stuff on the ground, and don't let the eyes get close to you when you're stealthed.
Queen Azshara Kill the puppet strings on Mind-Controlled players as quickly as possible, and avoid bad stuff on the ground. You HAVE to interrupt Azshara's Total Obedience ability.
Captain Varo'then and Mannoroth Stay out of bad stuff, focus on Mannoroth once Varo'then's dead, and keep adds off your healer and Tyrande.
Hour of Twilight
Arcurion Interrupt Hand of Frost, kill Ice Tombs, and stay out of bad.
Asira Dawnslayer Stay out of Smoke Bomb and on top of the light circles left by Thrall's totems. If you're a caster or healer, try to keep the tank or Thrall standing between yourself and Asira.
Archbishop Benedictus Spread out, dispel Righteous Shear/Twilight Shear, interrupt Smite/Twilight Blast, and stay out of waves.