Thrill of Possibility is a two-mana instant that allows you to discard one card while drawing two more
Sword of Feast and Famine is largely considered one of the best swords due to its untap-effect, and when you're running a snow-deck, Jorn essentially has that ability built right in
If your deck leans heavily on graveyard synergy (like self-mill or loops), make sure you also pack answers to graveyard hate and keep backup win plans available
Having good cards is the most important thing and so you try and take the best of the suitable stuff as you see it
This gives [c]Galvanic Relay[/c] a higher potential upside than [c]Act on Impulse[/c], as you can chain spells like [c]Pyretic Ritual[/c] and [c]Manamorphose[/c] to boost up your storm count, that way youll have plenty of cards to play for your next turn
The card draw clause pretty much guarantees that youll never run out of auras to play (assuming youre building your deck with lots of them), and the +2/+2 clause means that youll have a giant creature to attack your opponent with