Thanks you! :)
SPOILERS
Put heroes with high HP on the sides and low hp, high attack heroes (Spades and Clubs) on the back. The black king can be in any position since he has high HP and attack, but he's probably best on the center.
For the first few turns, try to keep most allies alive while using the most cards possible, and try kill a few enemies so you have more units than them (area attacks won't help you much here, since you will lower their HP, but not decrease their numbers). Focus on the minions first. The queen alone is no problem.
Some cards that are particularly good in this battle:
Defense for all (♠10, ♦10, ♣7) - Increase defense in early turns;
Heals (♥A, ♥3) - Use heals to revive allies later on;
Summons (♥2, ♥5, ♥10, ♥J, ♣4) - Keep them far apart, as white queen's attacks hit neighboring enemies;
Stone form+Taunt (♦4+♦7) - Can negate an entire turn of damage (use both on King of Diamonds preferably);
Confusion (♦8) - Use it on the queen, so she can attack other enemies, or even heal your allies!
Anti-magic wind (♣5) - You can use it to either remove Rook's +4 defense or to remove Knight's attack aura (-1 attack for all);
Invisibility (♣10) - If you're left with only 1 hero, use invisibility. You'll be invulnerable for 2 turns! With some heals and summons you can turn the tides!
Wind blast (♣Q) - You can use it early on to push the pawns out of the field!
Blizzard (♣K) - Freeze 'em all!
And remember that most of the time, it's better to use 3 average cards than 1 good card, because it will cycle more new cards to your hand.
Good luck :)