Resolve
Aftershock is a must have on cho giving you % increases to both armour and magic resist and a nice burst when you decide it's time to eat.
Demolish as well, is a must have. playing a champ with 7k hp... dont think i need to say much more...
Conditioning gives you a nice % boost to armour and magic resist so you can tank more.. duh
Overgrowth is HUGE when it comes to chogath, stacking both flat and % hp turns cho into an absolute monster with titanic hydra,

Sorcery
Ultimate Hat lets you stack your ult quicker
Celerity is nice to have for the added move speed in the eary game making your first jungle clear slightly faster than most junglers. in addition to having more move speed for ganks.

Other options

you can choose to take Transcendence instead of Celerity if you want more cdr in the mid game, but it will slow your jungle clear and lower your Gank pressure.

you can ofc take Font of life instead of demolish if you have a very squishy and auto attack reliant team and dont have a raka, sona or nami for heals.

when it comes to ganking a lane always try to get behind your enemy and anticipate where they are going to move and use your Q infront of where they are moving to. thus forcing them to either walk into it, flash or turn around.

with cho you have the open option to invade the enemy jungle at level 2 (level 3 is best) your Q slow in combination with your E damage and slow as well make it very hard for enemy junglers to deal with and either results in a kill or a flash, putting the jungler behind and making it harder for them to gank.

around 15 minutes or so you should be well situated on cho, with cinderhulk, mercs and working to titanic (if u dont have it already) cho really picks up here as a real pain for the enemy team to deal with. be ready for super ganks where the entire enemy team comes for you if you are split pushing or they know where you are in the jungle. never fear though cho doesnt lose his ult stacks anymore and grabbing a kill in the middle the enemy team is usually pretty easy (unless they heavy cc)

even after a terrible start in the early game cho can make a HUGE comeback, dealing boat loads of damage and soaking almost anything thrown at him. i have came back from a couple 0/5 games with cho where i either get greedy or my laners dont help with ganks. cho snowballs really well, dont give up!

by this point you are an absolute monster, nobody on the enemy team can deal with you in a 1v1 or 2v1 and your chances stuck in a 1v3 are still pretty good. there is no problem deleting enemy squishies (all are squishy compared to cho'gath xD) if your team is wanting to set up for a baron take make sure you hold it off until you have your ult. having an ult that hits 1k-1500 ontop of a smite makes taking and even stealing baron very easy.

Basic combo for every all in (should be a piece of cake)
(Legend)
aa = auto attack
q = rupture
w = feral scream
e = vorpal spikes
r = nom nom nom(feast)
th = titanic hydra

all in = q,w,e,aa,th,aa,r

this is pretty much the same for any fight, remember you're still a tank and it is still your job to peel for your squishies, make use of your Q range and silence to help your team out.

Cho'gath is a very strong champion if played correctly, stacking ap is a terrible idea and going full tank without a titanic hydra puts you in a very bad spot where you rely heavily on your team. Taking titanic for auto attack cancels is a must, with his %hp damage coupled with the hp based damage scaling if titanic allows cho to burst 2k or more in 2 auto attacks making it VERY easy to deal with adcs, mid laners or the champs we all love and hate, riven, yas, syndra etc.

so go out there and nom nom on some of those tasty yordles !!

this is still a work in progress, i will continue to update with pictures, videos and other helpful info if people are wanting more info or help. if there is anythin i have missed that you are wondering about, please post in the comments and i will work on it. ty :)