ok so now you know the builds what you do is you go and help ryze kill everyone by manipulation. use ryze to lure them in have him snare then start laying down your strongest attacks even though ryze usually gets the kill.

Get the Sapphire crystal at the beginning when you are summoned. If you want, get a few mana potions. Then, get the Ruby crystal or just finish Catalyst The Protector if you have enough gold. After you get Catalyst, work on Sorcerer's Shoes. Then, get the blasting wand or finish Rod Of Ages if you have enough gold. Work on Deathfire's Grasp or Rylai's Crystal Scepter, depending on how well the game is going. Afterwords, get Rabadon's Deathcap. If the game isn't finished by then (you should have won if your not stuck with feeders) then get Nashor's Tooth.