Need help for my Elementalis deck

[BTMcC]

I'm quite new to the game so I never expected it to be that good but... here it is, my first deck I've built on my own

I would love advice on this deck, it's fairly... okay, but, not that good.

Hero: Elementalis (42 cards)

Ally (21):
3x Frostmare
4x Stardust Transfuser
3x Rampant Krygon
4x Grimghast
3x Voracious Arachnid
2x Io Void Leviathan
2x Stardust Ampliflyer

Ability (20):
2x Life Infusion
2x Sacrificial Lamb
4x Bad Santa
3x Permeate
4x Shadow Font
3x Mind Control
2x Exaltation

Deck Code: 574136B

Also... any ideas on what items I could use, I couldn't think of any... I would also like to slim the Deck down.