It didn't seem too hard to begin with as everything is stacked in your favor. However if you are having trouble with an opponent use Tezzeret's Machinations deck!
I was struggling though the campaign using Jace's deck and only got about halfway. Switched to Tezzeret's and went 6-0 including a crushing win over the Jace X3 deck! None of the decks had an answer for even 1 Steel Overseer out let alone if I got 2 out! The scheme that lets you draw cards and all artifacts casting costs are reduced by 2 caused havok too!