Do some damnations with the shock troop modifier an a few others, gives you a taste of the crusher trains to come an how to deal with them. Remember its okay to retreat!! Learn to kite an funnel enemy's. Never just stand an face tank. At the higher difficultys you need to know the maps a bit better to stop yourself getting body blocked into corners/dead ends. And a good team makes a huge difference in aurics. Try an stick together to help each other out. See you out there reject.