Hello everyone and welcome to the Summoner build.I will explain to you how to play easy and good with the champion Cho'gath.This champion is a fighter/mage character but it makes a good tank because of the extra hp he gets from his ultimate "Feast".You can even solo at lane because of his passive "Carnivore" that regenerates hp per kill.So if you combine the "Vorpal spikes" and "carnivore" you can easy solo lane.

So the runes are half tank half dps,because you will still need some damage to make kills or help team.
So let me explain the runes:
-Seal of evasion because you will need a little dodge chance if you fight a strong ad like tryndamere or xin or lee sin or other carry,remember a strong tank dodges to rank
-Glyph of shielding because you will need magic resistance,not at begin to resist,you will need lot at mid game when the ap dealers have a lot and deal very much damage
-Mark of insight because you need damage with your first three spells
-Quintesences of swiftness because you need speed to help your allies,and if you want to run,when the fight gest ugly

The masteries are 9/21/0 because you will be tank,and the little 9 on offense gives you a little boost of damage.Remember the masteries are one of the most important things you have,without it you are underpowered than the other tanks.

So there are many items you can use as a tank,i know a good build for cho'gath but it's still better if you create your own item sets,i will tell you the normal cho build and some useful items you can use to make a good tank.
First of all,to be a good tank you first need to examine the enemy team before the game starts,to give you an example,the enemy team could be Teemo,annie,malphite,karthus,nasus,you can observe teemo what can be ap/asad(atack speed and damage),annie only ap,malphite tank,karthus only ap and nassus ad.When you see them it's clear,2 ad,2 ap,1 tank,you must start with some magic resistance because of the burst ap damage,because armor you can get much easy than the magic resist.If you see the enemy team ad are too op,it's time you get armor ,it is very easy to see what items you need after you see their build and watching their damage.
Now i will show you the items that you will need to counter the enemy team:
I The armor:
Thornmail=100 armor ,returns 30% meele or ranged damage as magic damage to the target,very useful in case the enemy has a carry
Frozen Heart= 99 armor,lesser cd at abilities 20%,and reduces enemy atack speed by 20%,very useful
Ninja Tabi=very useful,the only item with dodge,an armor at a low price
Guardian Angel=armor,magic resist,and an extra life
Randuin's Omen=armor,healt regen,and great slow when activated
II The magic resistance:
Banshee's Veil:hp,mana and block an negative spell every 45 sec,great for first hit or the enemy has a karthus in team
Force of Nature:greatest magic resistance,movement speed 8% and regen 0.35% hp every second,good when you remain low hp and try to run
Mercury's Treads:magic resistance,and tenacity that reduce duration of stun and slow
Guardian Angel:armor,magic resist,second chance
Hexdrinker:good,because block 300dmg when you are hit by a spell for 4 sec,when you are less 30% hp,again,when a ap try to kill you,you can outsmart him
Aegis of the Legion:A little armor and magic resistance for allies
That are the normal items,but sometimes you need hp,so buy Warmorg for life,one of the best items on cho tank.

Rupture is a very efficient spell because of stun and slow,you will need it charged before entering in any battle,you can even escape using it.(Q)
Feral scream=silence=kill ,if you have it you can stop some damaging ultimates,or even heals(W)
Vorpal spikes it's the most useful skill because you can farm with it and you can even solo with it.(E)
Feast=true damage,extra hp,remember to use it on mobs to get health stack(R)
F=Ignite=useful
So it's like this : Q=W=R=F

So the spells are :
Ignite=good when he escapes,just incinerate him
Ghost=If you want to run,run,so good
Flash=Quick escape,useful
Claity=if you run out of mana very fast,you need it
Claviance=NO
Smite=only jungle

Cho'gath is a good character,you can make him tank,mage,this build makes him a tank,and how to play him like this,so listen up how you need to play him as a good tank:
1.You must always go in front of enemy,and defend your team
2.You must not feed,because you will loose
3.Do not take kills from allies,i mean do not take all kills with your ulti,you are a tank,your carry need kills too
4.Farm a lot
5.When the allies dont have minion,and you are strong,you have to tank the tower
6.When you see you allies dead,run *****,run
7.When you see a cho'gath in enemy team and he is better than you,dont be discouraged ,at the mid of the game,you will show him who's the cho
8.In team fight you must channel on the most powerful target,and to watch when enemy like karthus,katarina,nunu and champions like those to use your feral scream
That is all.

It isn't so different at ranked,but you must not feed,always say ss,and never go after targets when you see all allies and enemies missing,and for your own security watch lanes to know when they are ss

Pros:
-A very good farmer
-Lots of hp from ulti
-Great pusher
-Good ganker
-Good jungler
Cons:
-Slow begin
-Slow moving
-You don't have a good escape
-Enemy wont hit you,because you don't have a taunt

So best allies to you are:
-Soraka,even if she sounds like a bad combination with Cho,it isnt,she can save you,you are saved a little from ganks,she can even give you mana
-Master yi,a lot of damage
-Sion,ap or even ad,great stun and shield explosion
-Taric,armor bonus,stun,heal and even damage +

Don't steal kills,don't feed,help your allies,tank mobs,turrets,players,remember you are a tank,and other players need kills,if you remember all these you will be fine

You have vorpal spikes,very useful for solo and farming,if you use this you will farm good

This is my build how to play cho'gath.I hope you enjoyed all and good luck playing cho'gath