Use spores on a target, then immediately blood altar them. That target will become immortal, and pause the spore decay timer long after everything else is dead. Also, whenever you're low on energy, just cast 3 blood altars and let the enemy shoot at you. You cannot die, as you can heal upwards of 1600 health per second when close to death, along with generating a ton of energy for both casting and [Quick Thinking].

Spam Miasma with reckless abandon.