Hearthpwn

Early game is key for being successful against aggro decks, i.e. face hunter or zoolock. The cards you really want in your hand at this stage are:

• Argent Squire
• Shielded Minibot
• (Depends on the matchup) Knife Juggler
• With coin and Argent Squire, or if you are facing another pally, Blood Knight.

Exceptions:

Do not play the squire when facing a priest, unless you also have the minibot. Northshire Cleric is the worst argent's nemesis.

As the game goes on, there are some cards that prove very useful, depending on the type of deck you are facing:

• Muster for Battle is best played in combination with Knife Juggler, as early as turn 4 with the coin.
• Ironbeak Owl is your only silence. Use it wisely, but do not hesitate to drop him quickly if you fear you are going to lose control of the board. A buffed Haunted Creeper is as good a target as any other.
• Truesilver Champion gives you some nice healing and allows you to remove almost any mid-game minion. Should you still have an Argent Protector on board, you can remove an enemy Loatheb, Emperor Thaurissan or Sylvanas Windrunner while potentially mitigating 2 damage.
• Mind Control Technician helps you quickly regain board control in case your opponent is over-extending.
• Aldor Peacekeeper is a solid 3-mana drop. Using one early can force your opponent to do unfavourable trades, thus helping you establish board control.
• Quartermaster, if timed correctly gives you a huge advantage against control and midrange decks.
• Defender of Argus combines very well with Muster to Arms and with your squires/minibots. If your opponent didn't remove Sylvanas, you can force him to deal with her by playing argus next to her.
• Consecration is your main AoE. Can clear an enemy zoo board and prepare the ground for your next plays. 

• Loatheb is a powerful card that generally gives you one-turn advantage on board, and Sylvanas Windrunner forces your enemy to play around it. While the first is usually good to be played on an empty board, Sylvanas works better as an answer to some enemy powerful minion, always take into account enemy silences.
• The Black Knight is always getting value as soon as there is some pesky taunt.
• Sludge Belcher is probably the best quality-price taunt minion in the game atm.
• Shielded Minibot is a wonderful mana-filler in this late game. 
• Quartermaster after your enemy has used the hard-AoE removals is a victory condition by itself.
• Guardian of Kings is a valuable 6hp-healing while having an imponent presence on board.

• Dr. Boom not much to comment about him, also good if paired with Knife Juggler.
• Kel'Thuzad, if you have board control he is the king. His 6 attack still keeps him out of BGH range.
• Tirion Vadin, also 6 attack. Vulnerable to silences, but a formidable foe otherwise.
• Avenging Wrath. If you play around its randomness, this is a perfect finisher. Paired with EqualityThe Black Knight can remove that uncomfortable taunt preventing your low-attack minions to finish your opponent off.
• Lay on Hands gives you draw and healing when you need it more.

Some ideas:

Muster to arms and Loatheb have a very good sinergy. If played after turn 10, you can drop a Knife Juggler first or even an Equality and clear your opponent's board. At this point, keeping the Quartermaster in hand means next turn you are ready to unleash an additional 6-8 damage to your opponent.

Avenging Wrath is the real secret of this deck. Everybody uses the Equality+Consecration combo, but using wrath instead can possibly mean finishing your opponent off in that same turn.