Note: the list can also contain common misconceptions. Be sure to post your own.
Opening the portal
[spoiler]-the middle "add guys" can sit on the sides of the portals to see the outside glass on both sides, adds on both sides, and adds in the middle[/spoiler]
Totems
[spoiler]-on totems, if a player is missing, the person on the totem can leave early and meet the person coming from middle with the brand. This can help save a wipe
-If the brand is lost at any time on totems, the knight will no longer spawn at 0 on the timer. This is because it is on a set timer itself. Your teammates should be aware of the knight spawning in the middle of a rotation[/spoiler]
Warpriest
[spoiler]-Right side is by far the easiest side to dps the warpriest. It should always be the first side to dps on. If your team gets him below half health, you should consider going to right side a second time to kill him[/spoiler]
Golgoroth
[spoiler]-Most people use a sniper to capture his gaze. A scout rifle is arguable the best tool for capturing gaze and destroying the venom orbs as opposed using the sniper[/spoiler]
Daughters
[spoiler]-the left plate on the oryx side is a good place to meet for dps on the first daughter. You can stand on top of it or behind it. It works better than the stairs because you're constantly being hit by the adds using the stairs.
-if you prefer killing the first sister, you could use the second sisters plate to shoot across for the most consistent headshots[/spoiler]
Oryx
[spoiler]-a quick countdown before detonating bombs can help synchronize the detonation so that nobody dies
-In most situations, it's better to die detonating a bomb than to not die at all
-you should typically never revive during the mortars phase. Wait until it's over to self res or revive anyone else.
-the bombs on oryx each do 1/16th damage. Shooting oryx in the chest does ZERO damage to him. However, it is necessary to shoot him as the bombs go off to keep his chest open so the bombs do their full damage.[/spoiler]