Template:Fireball strategy
Mages have a number of spells in their arsenal for dealing damage, such as 
Arcane Explosion, Frostbolt, Cone of Cold, and of course, Fireball. A mage must carefully consider which spells to include in their deck. While other spells do damage to more than one minion, or have secondary effects such as Freezing, or have restrictions, such as Ice Lance, Fireball has no secondary costs or effects, making it one of the most consistent spells in your arsenal.
A deck including Fireball is very unlikely to include two copies of it and no copies of any other spell. For this reason, it's important to see what spells we want to pair Fireball with. Fireball, being a single-target spell, shares a similar spot in the deck to Pyroblast, Frostbolt and sometimes Ice Lance. Pyroblast is very expensive, so it's unlikely to want to deal with the same minions as you would with Fireball. Frostbolt deals 3 less damage and freezes for 2 less mana - which leaves Fireball as the better choice, unless you think that 6 damage is 'Overkill', or you are using Spell Damage minions to boost the power of Frostbolt to higher damage.
Fireball does a large amount of damage to a single creature, which leaves us vulnerable as a mage to a large number of smaller creatures. A deck that includes Fireball should probably include some number of cards that help with smaller minions, such as Arcane Explosion, Blizzard, or Flamestrike.
Fireball is widely considered among the best damage spells in the entire game. It is extremely cost efficient (compared to Pyroblast, Lava Burst, or 
Forbidden Flame). It is also very versatile, able to be aimed directly at an opposing hero, unlike Stormcrack or 
Arcane Blast. For these reasons, almost all Mage decks, from the most basic to the highly optimized, include two copies of Fireball.
This template contains Strategy content for these cards.
Remember that this is just an archived content of Strategy section that was supposed to be removed following the decision in Hearthstone Wiki:Project 13. It's up to you to review the content and keep them for a project in the future. Details to follow soon, once Project 13 is completed.