Try to be proactive, not reactive. Offence usually trumps defence in this game, as you're on a card clock, but the monsters aren't. The best status effect is "dead". You can't hang back, shield & heal, as your resources are limited, and the enemy's are not. Some will summon more if given the chance. You won't have to prevent or heal damage that you can avoid or preempt through clever timing, positioning, card selection, and item use.