Mulligans
General Mulligans
I'm not going to sugar-coat it, this deck has some issues when going first.
Regardless, you should almost always mulligan for your totems and your Death Knight.
You should aim to have your Death Knight in play as soon as possible to benefit from the Hero Power, even if the Battlecry seems like it will go to waste.
Simplified, this deck has 2 goals.
Maintain board control, Evolve your minions, rinse and repeat until lethal is available.