Hearthpwn

This deck is based on a Spooky Mage deck I found here with a few adjustments to suit my own preferences & play style. 

It depends heavily on hero power enhancement and big spells. Initial starting hands are very important, so if mulligans don't produce viable cards for the first few rounds, it's very difficult to win. However, I typically manage to get enough to play successfully. 

There are a few strategies I try to build through a game. 

• Hero power: Build as high as possible. Wildfire is an obvious boon. Ideally, time Wildfire with Commander Sivara. Magister Dawngrasp w/ the +1 damage for honorable kills. Rune of the Archmage often provides additional Wildfires, and you can use Grey Sage Parrot to repeat that more than 2x as well. I usually end games with my hero power at least 6-8 damage.  Using Mordresh can win the game, or at least set the game up for a win withing a couple turns.
• Big spells. Use mana reduction as much as possible - Shivering Sorceress, etc. Use minions like Greysage Parrot or Clumsy Courier to play cards for cheaper. Use big spells themselves to produce MORE big spells that cast without any additional mana from you - Rune of the Archmage or Sunwell. 
• Volatile Skeletons: Another potential game winner, definitely a board clearer w/ Deathborne & other spells mentioned above. 
• There's of course no good healing/health mage cards, and this deck has mostly mage class cards b/c of the requirements to gain the later game rewards. However, various spells that freeze opponents or Solid Alibi can delay much damage while you're setting up bigger plays or haven't pulled a viable card.