How do I counter aggro decks?

[Cakes]

I usually play control mage, and aggro decks are something I noticed I commonly lose to. Anyone have any strategies/specific cards/ card combos in mind?

[Devin]

First of all, removal. Even just things like firebolt helps.
If you can kill their 2 drop with a firebolt then that's great.
Second, guards. Aggro wants to hit you, not make trades. So force those trades.
Third, prophecies. If you really want to stop aggro, run 3 shrieking harpies in your mage deck.
The more you can slow the fight down the better off you are.
Oh, and lastly, don't hit them. If you're playing control, don't break an aggro decks runes until you're ready to kill them.

[Zsrai]

Control should beat aggro. Use the control elements of your deck to keep the board clear(ish) and your comeback mechanic to come back and win after draining your opponents resources (mostly cards in hand).

[eRe4s3r]

Important against aggro is to gain board control (even if it wastes 1 or 2 mana) and FORCE them to make trades. Once your aggro opponent makes trades and once you have board control in both lanes you have won. As control player YOU have control creatures (I hope) You need to force getting to this with the 2/1 give ward -> wards (forcing out silence), sacrificial thingy (0 mana deal 5 can be a huge game-changer) harpy (obvious), and obviously stuff like Ancano and "if your next card has color X draw a firebolt" dudes etc. as well as the silence then deal 1 damage creature. Finally you need a threat, a threat that the enemy CAN NOT IGNORE for more than 1 turn (I use makath gain 2 rush 0 mana minions on attack) for this, as it combos with the supreme summoning dude. The item that gives +5/+0 last gasp return to hand is also absolutely vital in board controling, especially with the above mentioned warded creatures, after they've been silence your enemy will likely be inclined to ignore them, but ignoring a 7/1 is not very smart ;)

You won't always win against aggro, but aggro has a horrible time against control usually. And aggro generally will also have a horrible time dealing exactly 1 damage. I've seen hard removal used on my 2 mana warded 2/1 buffed to 7/1 because of the +5 item last gaps item on her. I've seen it even used on a 5/4 buffed 1 mana creature, buffs that gave me card draw, and even card removal because 1 hard removal gone from enemy deck....

If you want more in-depth answers you should show us your deck ;) But generally don't despair, if your deck fails at control you need to fix your "front" a bit, the 0 to 4 mana is where you lose against aggro. In this range your control deck needs to be on-par with an aggro deck, later on you will have heavy hitters that aggro can only hard remove, and if they are not guards then that's a precious wasted hard removal.

It's also important to have a combo in your deck. Rush 0 mana (raid leader) + last gasp +5 dmg can end the enemy for 5 mana. Summoner + 0 mana creatures, extremely evil. Doppelgänger can be a total game changer if you have ancano out (that's 10 damage for 5 mana) etc.

You need to put HEAVY hitting combos in your deck. If you can deal 15 or more damage in 1 turn regardless of guards all the better. But obviously this can be luck dependent, the base deck of yours should be control setting up for the combo.