Tips
PALADIN
Player
-A lot of the really good cards are rare.

Against
-Keep their board clear (buff targets)
-Watch out for turn 4, play +5 health minions (Truesilver, Consecration, Hammer of Wrath)
-Avenge (+3/+2 friendly minion), Redemption (reborn), Repentance (1 health your minion)

MAGE
Player
-Aggrasive (Mana Wyrm, Frostbolt and Sorcerer's Apparentice)/ Control (Fireball, Poly, Flamestrike)

Against
-Counterspell, Mirror Entity, Duplicate (clone two friendly minions), Spellbender (change spell target to 1/3), Vaporize, Ice Block, Ice Shield. 3 mana each.

ROGUE
Player
-Usually very aggrasive
-'One dimensional'

Against
-Big, final burst of damage is good since they use up their health trying to maintain advantage
-Reduce their health as much as you can
-Assassinate (5 mana)

WARLOCK
Player
-One of the most annoying and OP classes

Against
-Keep pressuring, if they're using the Hero Power, you're not doing enough pressure

DRUID
Player
-Slowest class, reply on late game

Against
-Silence is golden

PRIEST
Player
-Almost always controlly style
-Have card advantage since their minions live longer

Against
-Always keep the board clear
-Punish them for their slow openings

SHAMAN
Player
-Strong rare cards
-Buff cards to buff totems = profit

Against
-Clear board, in fear of buffs
-Fire Elemental (6)

HUNTER
Player
-The fastest and most aggrasive class

Against
-Snake Trap(attack minion), Explosive Trap (attack hero), Snipe, Freezing Trap, Misdirection
-Multi Shot (4), Explosive shot (5)

WARRIOR
Player
-Makes it hard for enemies to finish you off, but you have a lot of burst potential

Against
-Just play aggrasively and kill their minions, never try to race them to their death