Order of Upgrading?

[tinkady]

yeah upgrade all your novas, then buy Puppychow's Entropy Rainbow http://elementscommunity.org/forum/index.php?topic=1748.0
I use a variant of that right now, and win most of the time vs FG's (probably about 60-70%).  His deck probably wont be that effective unupped, so you should keep using your old one until his starts working better. If you use Puppychow's deck definitely upgrade your Otyughs and Hourglasses first.

[bojengles77]

If you want to go with a rainbow FG deck, which i recommend, you need 6 supernovas, and 2 olite otyuhgs / 2 electrum hourglasses are your best bet for first upgrades. Then do cards like firefly queen and fallen druid, and go from there.
NOVAS are most important , since the deck can't function without them, but otyughs and druids get a huge boost from the upgrade.