Spells: If you want, you can get Ignite instead of Exhaust, but I prefer Exhaust.

Masteries: If you prefer Ignite,get lvl 1 Critical masterie.

Skills: Siphon of Destruction is your strongest and better skill to recharge the shield. Creeping Death helps a lot with the additional defense and magic resist.

Runes: I'm not good with runes, but I suggest hp regen, hp, armor and magic resist.

Items: Start with Doran's Shield, it's very good early game.
Warmog's will help a lot with HP and HP regen (remember to get stacks).
Get magic penetration boots to boost your skills, but you can get magic resist with you want.
Sell Doran's Shield and buy Omen, you will need defense.
Force of Nature improves the HP regen and gives magic resist (if the other team don't have mages, get anyway, the HP regen helps a lot).
Rylai's gives you HP and AP.
Last item: If the other team has tough mages, you can get Guardian Angel, but if it doesn't, get Sunfire.