The new Tavern Brawl is AMAZING!
Here are my personally recommendations for deck building.
1. Pick any class, but Druid and Mage work the best, Shaman the worst.
2. Put in ALL THE SPELLS! Seriously, ALL OF THEM!
3. Put in ALL THE TROGGS! Troggs get a bonus every time your enemy casts a spell.
4. Put in ALL THE GNOMES! You want to draw cards. Only use the Dalaran Mage is you have a lot of Direct Damage spells. (Mage/Hunter/Rogue)
5. SMASH FACES!