"Afraid of the dark? That's my shadow!" Welcome to my guide for a pretty much pure tank . This is my first guide, so if it sucks then well..I guess it's an excuse. Cho's not the strongest early (But he is pretty damn strong :P) but mid-late he's awesome.
I really hope this guide will be useful in someway. So just enjoy. :)
And btw look at this sexy beast!

Since utility is probably the most important thing in this game... well this is just awesome to have you'll catch just about if not every enemy.

Just a basic for any AP in the game tank or not, really a must.

They work on pretty much on all champions in the game. And well your a tank so this is kinda obvious.

Again work on every champion, I prefer this one for the early game but you could just as well get Greater Glyph of Scaling Magic Resist for late game.

Invisible text!!!!!!!!!!!!!!!

Pros + Strong Mid- Late + Awesome legendary skin + Great ult + Da CC masta + Good lane period with: Carnivore + Not easily gankable + Nom's everyone :3

Cons - Bad early game - CAN be bursted down easily - Item dependent - His classic skin is ugly as...The Void - CAN be shut down completely in lane - Rune dependent

The Offensive Tree:
Sorcery: This + Frozen Heart and Spirit Visage(If you choose to get it.) = CDR! (I know it caps at 40 but..)
And the next two are just basics for an AP top.
Not too much to be explained for the Defensive Tree,
the things you could put in instead I guess are: Unyielding , Block and Legendary Armor .

Well I've changed my mind for the 300'th time..Oh well, To me these are the best choices. Why? Well most people go with the ever popular Flash and Ignite Why don't I go like that? Well because I feel that the Teleport will benefit the team and you so much more and ganking with it is soo awesome, if someone places a sight ward in a brush, and suddenly a wild Cho'Gath appea- "nom nom nom". And now about Ghost, I just feel that Ghost plus those 3 Greater Quintessence of Movement Speed are just a better choice than Flash because you might be running away from a fight but they're catching up to you or your teammate by popping Ghost you'd be able to land a quick Rupture and get away fast. Or if you're trying to catch up to someone using Flash and then Rupture isn't as accurate. (In my opinion.) You could also consider : Just to slow or lock down your prey. Also great for ganks, but you should really only get it if your support doesn't. Or you could take Flash and/or Ignite no one's stopping you. (I just don't like them on Cho'Gath).

You're going to take these 90% of the time. If the enemy team doesn't have much or any MD then take the Ninja Tabi

Awesome item, a great passive that gives you HP,Mana and AP.

An must if going tank Cho'Gath. Gives you armor,mana and a passive that reduces nearby enemies attack range by 20% !

"The" tank item. Awesome passive and 1k HP, what more do you want?

An item i prefer on all my tanks. Burning yo foes FTW!

Nice chunk of health,AP and slows. A very useful item.

The abilities are really up to you how you work them if you have 6 stacks of Feast you could just as well open up with it, and in team fights you might wanna try too hit the healthiest target with Feast. You should of course always have Vorpal Spikes activated.

When laning Rupture is your harass but don't use it to often where as it's very mana dependent early, and when you do use it try too be really sure that it'll hit. You can win just about every lane whether it be against Elise or Renekton. But if you're having problems just ask for ganks or let the minions push to your turret and then farm them.

When farming early don't use your abilities too much until you get catalyst the protector, You can just Rupture and then Feral Scream and you get most if not all the minions. once you hit 6 you should start by using Feast on minions because it's dangerous to wait too long because when you have only 3-4 stacks you're fast losing them.

You should never be too confident...Well unless you've got 6 stacks of Feast then you're well... A beast you should always go ahead of your team, and tank turrets and Baron and stuff. having blue buff while top is very important but while laning always remember to ask for it before you just snap it.

Difficulty:Medium-Hard

Counter items and spells: Quicksilver Sash, Negatron Cloak, Banshee's Veil, Cleanse

Elise Thrives on your Feast stacks. Get her ganked often early she doesn't have many escapes early on so just try to shut her down before she gets too strong.

Difficulty:Easy-Medium

Counter items and spells: Chain Vest, Exhaust, Flash

You have to Que up at least 100 times before facing a Riven. (Stats may not be accurate ;D)But if you face her it's not going to be hard. But good Riven is nothing to play with.

Difficulty:Hard

Counter items and spells: Quicksilver Sash, Frozen Heart, Ignite

You don't often see Warwick top, but when you do you should be cautious, for his life steals are one of the most annoying things in this game. And also his Hungering Strike deals dmg based on the target's maximum health so that will annihilate your Feast stacks.

Difficulty:Easy

Counter items and spells: Negatron Cloak, Flash

You pretty much win every lane against Malphite, but watch out when he's 6 for his Unstoppable Force is a good initiating tool and help junglers a lot with their ganks.

Difficulty: Easy-Medium

Counter items and spells: Aegis of the Legion, Chain Vest, Negatron Cloak, Exhaust

This can be an easy lane. Just start with your Vorpal Spikes max them 1st, then take Rupture for kiting or running away and your Feral Scream for dem silences and ultimate CC.
Just make sure to get her ganked as much as possible pre 6.

Difficulty:Easy

Counter items and spells: Chain Vest, Barrier, Exhaust

He was easy pre nerf but now after his ulti nerf he just doesn't feel like much of a threat. (I know the nerf wasn't really major but still.)

Difficulty:Medium

Counter items and spells: Randuin's Omen, Frozen Heart, Ninja Tabi, Exhaust

He can dodge your Rupture really easy, so you should really try not to use it too much. You as Cho'Gath have much more sustain but in a 1v1 you'll probably lose.

Difficulty:Medium

Counter items and spells: Exhaust, Chain Vest

Use your Rupture every time he uses his Judgment to nullify his Spin2Win, Avoid dying at lvls 1-3 because of his snowballing. Once you get enough armor, just harass him with auto attacks and use random Rupture's to cancel his Perseverance.

Difficulty:Easy

Counter items and spells: Randuin's Omen, Frozen Heart, Exhaust

He's pretty easy pre 6, so try to shut him down as early as possible because he gets a lot stronger at 6.

Difficulty:Skill

Counter items and spells: Chain Vest, Exhaust

This is a back and forth lane and really based on skill on who wins, You can probably win the lane easily but watch out when he's six for his Dominus, for it's incredibly strong.

Difficulty:Easy-Hard

counter items and spells: Randuin's Omen, Frozen Heart, Flash

You might be wondering why i made it an Easy-hard lane it just really depends on the skill of the Xin Zhao you're facing just try and out farm him and wait for to use his Three Talon Strike try to rade.

Difficulty:Medium

Counter items and spells: Chain Vest, Exhaust

You should outfarm him. And any poke he does will/should be gotten back with Carnivore. And just play safe till lvl 6.

Difficulty:Easy

Counter items and spells: Vision Ward, Oracle's Elixir, Chain Vest, Exhaust

Yes I'm afraid you'll be facing one of your fellow voidlings :( . Oh well, you have more sustain the great true dmg and you're tanky enough to soak up his damage (A sponge if you will). If playing right you'll win this lane 90% of the time.

Difficulty:Easy

Counter items and spells: Warmog's Armor, Ignite

Cho'Gath is the perfect counter to Yorick. His Omen's are annoying as hell though, just try to last hit them and then zone him out.

Difficulty:Medium-Hard

Counter items and spells: Frozen Heart, Randuin's Omen, Ignite, Exhaust

She counters you early, just stay safe till later on when you can trade and win her.

Difficulty:Easy

Counter items and spells: Chain Vest, Exhaust

You mostly see her in the jungle but occasionally she comes top. You should out farm and trade her.When she charges her Vault Breaker throw a Rupture right in front of you and follow up with Feral Scream she'll take some damage and you might even kill her if you're lucky

Difficulty:Medium

Counter items and spells: Vision Ward, Oracle's Elixir, Frozen Heart, Exhaust

I HATE THIS LITTLE BASTARD SO MUCH ! No but seriously i hate him his Noxious Trap is the most annoying skill in the game. But you can win this furry bastard just buy a Vision Ward or Oracle's Elixir.

Difficulty:Medium

Counter items and spells: Banshee's Veil, Exhaust

You should outfarm him and when he's facing you autoattack him so you don't get poisoned by his Poison Trail. And remember NEVER CHASE Singed !

Well this has been my guide for Cho'Gath I hope it helped you in some/any way and that you enjoyed reading it, if you liked it then pls give it a plus 1. :D. Will be throwing in some more features!

Special Thanks:

Sisask (For help in the comments.)
HoserHead (For help in the comments.)