The Archer Queen is essentially a more powerful version of the Archer. She is the second Hero, being unlocked at Town Hall 9. In addition to possessing much higher damage and hitpoints, the Archer Queen also shoots 1.5 tiles farther than a normal Archer (5 tiles instead of 3.5 tiles).
Strategy
Offensive Strategy
She has a better range than an Archer (5 tiles instead of 3.5), so a good strategy is to place a group of Giants, P.E.K.K.As, Golems, or the Barbarian King as a meat shield, then a group of Archers, and finally the Archer Queen.
You can use an Archer Queen with a Royal Cloak Ability in raids to help you clean up buildings for 50%. As damage approaches 50%, simply deploy your Archer Queen and use the ability immediately so that she can destroy a few extra buildings, not taking damage at all.
Defensive Strategy
The Archer Queen is more suitable for defense than the Barbarian King because of her faster attacks and harder hits, and she is able to attack from a longer range (as well as being able to strike air units), but she has dramatically lower health than the Barbarian King.
Protect your key defenses by keeping them more than 5 tiles away from the nearest open space, so the queen cannot snipe them.
Keep your Eagle Artillery away from the Queen’s altar so that opponent cannot destroy both with Electrone or Blizzard