This deck is very simple and easy to play. Draw and build up your C'thun untill you have combo in your hand. (Alexstrasza + Brann Bronzebeard + C'Thun + Shadowstep.
Ofcourse the entire combo is super overkill, but you have all these cards just in case.
Don't be afraid to use C'thun to clear off opponent's board that's why you have Doomcaller in deck.
And if you see that you are playing against OTK deck as well and they are deeper into draws than you, play Brann + any of the drawing cards to outtempo your opponent.
I would also suggest using Bonemare on Twilight Elder so it's harder to remove.