You'll want to start with the boots, tome and health potions to help you survive and harrass either bottom or top lane. Wait until you have enough to get your sorcerer boots and, if possible, another tome. Upgrade to hextech and then try to either get a needlessly large rod or a giants belt. Get wooglets next and a kindlegem for extra health and some more cooldown reduction. Upgrade to spirit visage or upgrade your crystal next (the health regen from visage is awesome though). Upgrade to will of the ancients, the spellvamp will give you a lot more health regen from skills. The last one is based off what you might be facing, either armor(Zhonya's) for more ad offense or MR(Abyssal) for more ap team. I do love Zonya's though, because it makes you untargetable just like his pool. This can really upset people lol.