Basic Health, AP, and Magic Pen will be useful for beginning game. You'll have a lot of AP available until you start your actual AP items.

> Catalyst the Protector is definitely needed on Orianna, you benefit greatly from the health and mana. Anytime you level up, it's passive procs and you can stay in lane longer.

> Ionian Boots of Lucidity with Morello's Evil Tome give you your 40% cooldown, plenty of AP and a bit of mana regen.

> Rabadon's Deathcap is definitely needed. All that extra AP turns you into a killing machine. (No pun intended)

AFTER DEATHCAP:

> Void Staff is generally a good item to grab if you haven't won your game by this point. Plenty of extra Magic Pen goes a long way.

> If you're having terrible issues with mana grab an Archangel's Staff, a Lich Bane or a Banshee's Veil.

> Banshee's Veil, Rylai's Crystal Scepter, or anything for survivability is good at this point.

Obviously everyone likes their own combination of Summoner Spells. Here is what I use and why.

I REALLY enjoy Clarity so I can stay in a lane for a long time and harass like crazy, also you can throw up clarity to any low mana'd ally.

For the obvious reasons escaping.


Other Possible Spells.

Teleport

Clairvoyance

Ghost

This bit is easy.

> Stay in the back

> Spam your ball: Throw your Q and W around while using your E to shield any carry who somehow got into the middle of the scuffle to save their butts.

> Use your ULT when two or more enemies are grouped up. Using your ult on the whole enemy team is a beautiful thing.

> If you end up needing to escape in a hurry use your E on whoever is in front of you then use your W to make everyone run super fast.

Use your Q followed by your W on the caster minions... you'll kill them every time. ((Approximately after level 7 or 8.))