Mulligans
General Mulligans
Fire fly is instrumental in effective use of mana and triggering elemental effects
Mana wyrm is the strongest one drop in game
Frostbolt is insane early game removal
Golakka is a strong two drop which kills aggro
Tar creeper prevents cumulative face damage
Aggro Mulligans
General mulligan is always in preparation for aggro
Midrange Mulligans
Glyph for a removal spell to regain contol of board you will win in the long run
Combo Mulligans
Tar creeper doesn't necessarily play a big role against combo
Control Mulligans
Mulligan should be the same except avoiding tar creepers and you can afford to keep greedier cards, if you go second it is acceptable to keep jaina
Elemental mage is a fairly new archetype actively being pushed by blizzard and a safe bet for future playability. This version is competitive against any meta deck with the exception of jade druid. Elemental mage is a very flexible archetype able to outlast faster deck with value establish aggressive board pressence and burn down enemy heros.
Elemental mage is a fairly cheap deck if you lack certain cards consider the following:
Another tempest instead of pyros
Firelands portals instead of blazecallers
Flame geysers instead of glyphs
Any 3 drop for ooze
Yogg-saron or Togwaggle for frost lich jaina