Walling up with defensive minions so that I can get to 5/6 mana and surprising the opponent with in your face fire spells.

[[Avatar of Water]] has amazing mobility, allowing it to be exactly where it needs to be.

Throw around powerful close range removal like [[Disintegrate]], [[Mesmerism]] and [[Poison Nova]].
Hit with [[Lava Flow]] and [[Flame Strike]] the best possible angles.

AoW can be set up to reach most of the board. Any dedicated fire sites can be put to one site to not break the body of water too badly.

You don't need to utilize AoW's effect every turn, the quality of water minions is good enough to build pressure.

[[Shellycoat]], [[Tufted Turtles]] and [[Failed Mutation]] are able to ignore [[Poison Nova]] and take some small splash damage from other spells
Most high costed water minions are potent enough to be threats on their own.

---------------------------

I am starting to think that some site removal is a must in decks these days, so I've reluctantly added [[Raze]]. I did have [[Heirloom Lost]] but it added some stress to making sure I have a body of water and 2 fire affinity.

Also because of those two requirements, I am running [[The Colour Out of Space]] and the relevant castles. This also allows me to have a [[Dispel]] and [[Disenchant]] in my collection

Thermodynamics

@Ortail