I'm a Hydromancer, AND an Aeromancer.
For Air Magic, I usually run a Dual-attune or Ether Progidy build, so's I have energy a-plenty for casting all them lovely Lightning Orbs and Blinding Flashes. Generally, I run something like this:
--> Lightning Orb - massive damage, fairly spammable
--> Enervating Charge - fair damage, weakness is sexy
--> Blinding Flash - God. Blindness makes Aatxe cry.

Abyssals will want to tear you a new one for it too.
--> Shock Arrow / Lightning Strike / Lightning Javelin / Windborne Speed / Whirlwind / Gale - either another spammable damage spell, or a defensive spell depending on the area. Arc Lightning is another spell I'd consider if you're lucky enough to party with a Hydromancer, or Lightning Hammer 'cuz it looks cool. And hurts.
--> Elemental Attunement
--> Air Attunement
--> Aura of Restoration - minor healing (meh), but an important cover for Attunements
--> Res of some sort (Rebirth or the hallowed Signet, ideally). If you don't take res, then undoubtebly you're gonna be the only one left alive.
16 Air Magic and 13 Energy Storage are all that is needed (the last 3 in Protection if you use Rebirth), and an Insightful Air Staff of Enchanting is the most obvious choice of weaponry.
As for Hydromancy, I generally set out not to deal uber-damage (Ice Spear does that by itself

), but to support the party and cripple the enemy. To this end, Deep Freeze and Ice Spear I take along for damage (Deep Freeze is such an insane Area of Effect, it makes them AoE test dummies weep), then fill my bar up with whatever Water spells seem best for the area. Armour of Mist is a powerful spell for protecting your berobed ass, Ward Against Harm is an incredible all-round elite (especially in the Ring of Fire... Mahgo Hydras and Sparks become a laughing stock with this ward around). Blurred Vision is good in melee heavy areas, having a long duration and decent AoE. If damage is what your party needs, then you can happily slip Ice Spikes, Vapour Blade, and Icy Prism (ooo, pwetty colours...) onto your bar, and power it all with Ether Progidy.
Have fun zapping/freezing enemies to death, young elementalist.
