Hi there,
I made a version of Azorius Spirits here (3rd post down):
viewtopic.php?f=52&t=10292&start=300I go over some of the things that the deck can do, and the
Invocation of Saint Traft is a big finisher if you draw it. Slapping it on a flyer (especially if hexproof'd with Rattlechains) can take the opponent by surprise quite well. Try to think of it more as W/U's version of
Exquisite Firecraft, a finisher more than a play on turn 3. Spirits is a fun aggro deck that can win by turn 5 if you play Invocation right.
I'd also suggest running
Reflector Mage in W/U. It can set your opponent's plan back 2 turns if they used a creature to stall you/race you.
As a start I'd say -3
tightening coils and go +3
Reflector Mage. If you want to focus on the flash/flying aspect of the deck, then -2
Knight of the White Orchid and go +2
Dimensional Infiltrator (almost like having 4 copies of Rattlechains!)