AP Cho is the way to go, feel free to ditch the lich bane for some tanky items such as a force of nature or thornmail if needed. This is a full ap build. For some reason although this system does not show the 30% ap form rabadons and the 3% of mana from the archangels which would put your ap to 600+. remember that if you get fed and can swap out dorans ring for maybe a warmogs or the other items I said above you'll be laughing. AP cho is great for many reasons. his rupture has a 1-1 ratio so all of you ap goes into rupture this means if you have a ap cap build you can hit over 1300 dmg in just your rupture. It is critical to max rupture first as this move scales 1 to 1 with your AP and also causes a slow, this doubled with Cho's silence and feast can be very deadly. Cho's ult is true dmg and the amazing thing about Cho is that his AP get converted into this true dmg making him able to skin tanks alive if needed. this is a pretty boring build but it works for someone who is new to Cho. also if you're having problems with taking a lot of damage then get merc treads instead and possibly a Rylais instead of Archangels or Lichbane for the slow. I normally replace the dorans ring with a lich bane and buy the Rylai's first anyways. Omnomomomomom have fun feasting :)

Ok so tank Cho is a beast but also you're sacrificing survivability for damage. If you get Cho's feast stacks to 6 and max your feast when you can you're pretty set on hp. but what of magic resist because and annie is nuking you? well force of nature and build it quick, or if some OP tryn/Yi is too quick just buy a thornmail, your damage and their own self infliction should easily save your hide and often.

AP Cho requires many different builds depending on the other team so this one will not apply to everyone. But if you're new to Cho this is a good place to start.

Flash is a noob spell no doubt about it, it is overpowered and silly. that being said you can flash over a wall to save your life or just flash towards an enemy that may other escape you if you hadn't. ignite is needed because of the talent tree. you receive 10 extra ap while its on cooldown, this is amazing early game and can give you the upper hand. I don't mind people replacing the nooby flash spell with something more useful such as Ghost or Clairvoyance.

Vorpal spikes and rupture.. such an amazing combination! Rupture will one shot a group of minions mid game easy and early game your vorpal spikes will land several final blows. as Cho you should have near most or most minion kills if you make use of your abilities. Don't worry about wasting mana due to the fact that Cho's passive regenerates HP and mana per kill so its easy win farming. Don't forget to feast on minions.. such a simple mistake. you want to get to your 6 feast stacks ASAP no matter what. This being said, if you sense a battle with an enemy champion incoming then just save the feast for insane true damage during the battle