Mulligans
Handlock is a broad archetype that relies on using the Warlock Hero Power throughout the game to consistently maintain card advantage over opponents. Having additional cards in hand provides more possible plays each turn and allows for a more reactive playstyle due to the increased likelihood of having key cards in hand.
Most of the early turns will consist of simply using Life Tap, sacrificing Health and giving full tempo advantage to opponents. To counter this, a large number of healing and board clear effects such as Earthen Ring Farseer and Hellfire are used to stabilise later in the game. In addition to board clear and healing effects, other high value cards such as Twilight Drake and Mountain Giant are frequently used to to advantage of the large number of cards in hand, often requiring multiple cards for opponents to answer, furthering cards advantage.