Since i can't find a build that fits me, i will write the build i use for Orianna.
I play Orianna my self and i use this build and i have won alot of my games with this build.

Pros
Good farmer
AoE damage
Can support too
Great harasser

Cons
Can be confused if you don't know where the ball is
Squishy
Short Range
New playstyle and hard to learn

I go with 9/0/21 because i mean that Orianna need some more things from the Utility tree than Defense tree. And cooldown reduction, spell penetrate and AP from the Offense tree.

I prefer them because Orianna is very slow at the beginning, and if you have to go back because you have to heal or get some mana. Then it's good to have Teleport. And i really prefer run because flash got a long Cdr.

Good summoner spells too:
Flash is good because u can "blink" to the otherside of the wall if you want to escape and it's a good thing to chase too.
Clarity is good too because Orianna got mana problems at the start of the game, and will have it a very long time in the game.

Start items

Core items

Late game items

I start with Amplifying Tome and a Mana Potion, then after a while i upgrade Amplifying Tome to Fiendish Codex, and after i buy Sorcere's Shoes, not Ionian Boots of Lucidity because we have Morello's Evil Tome to take the Cdr (Remeber to upgrade Fiendish Codex after buying boots).
Buy a Blasting Wand and upgrade to Void Staff because we need the mage pen. it gives and ofcourse the Ap. Later buy Giant's Belt or Blasting Wand again (I recommend Giant's Belt) and upgrade it to Rylai's Crystal Scepter. Now we buy Rabadon's Deathcap, but i would recommend buying Blasting Wand first because of Needlessly Large Rod price, but you can buy it after Blasting Wand. After you bought Rabadons Deathcap, buy Catalyst the Protector and upgrade it to Banshee's Veil or Rod of Ages.

Try hit the three last minions (Ranged minions) and try if you can hit the three front minions (Melee minions) too. Then all the minions got half hp or less, and if your opponent is close to the ball use Command: Dissonance.

(Pictures coming soon)

This isn't the end i will edit later, but not now. Btw it's my first time to write a build in mobafire. Hopes that this build will help you guys out there, and please try out my build before voting.

Rune chapter coming soon
Pictures