DH Soul Slayer

Mulligan for mana curve and look for specific cards that are good in your specific match up. Mass removal and life gain is great vs Aggro, Consume Magic and Kayn vs Taunts, Blade Dance and damage buffs vs large minions (like Druid Guardian Animals). 

If you are seeing less aggro the Ashtongue Battlelords can be switched out for Wand Makers or Vulpera Scoundrels. 

Play for tempo and try to keep the pressure on. Push damage when possible and only trade when absolutely necessary. Be judicious with your mass removal and force them to trade/remove your minions. Also vs aggro look to pump up your Aldrachi Warblades for max heal.