This is an Infect deck for the patient player.  Rush to get your first poison counter, with Blighted Agent, Ichorclaw, the Stingers, or a well-timed Virulent Wound, then relax.  Block freely, and keep yourself alive while your proliferate does the work for you, or use the fliers and Blighted Agent to wear away your opponent's resolve.  Save your caress of Phyrexia for the endgame - don't use it until you're guaranteed to win.