Pros:
-2 Crowd Control (CC) abilities.
-Naturally tanky thanks to ultimate stacking.
-Decent laning phase due to passive.
-Good base damage.
-Ultimate is a true damage nuke.
-Buff/Dragon/Baron security with ultimate.

Cons:
-Q needs practice.
-Inconsistent vs high mobility champions.
-No escape other than Q.
-High mana costs.
-Upon death, loses half of the ultimate stacks.
-Prone to kiting.

You can either activate E and push or deactivate and farm normally. E is also good for harassing and continuous poke. If you're zoned, farm with Q only if you are going to get 2 minions or more. Otherwise let the wave push to your tower. Cho'Gath has relatively easy time farming.

Although Cho'Gath will be built into a Tank, he deals quite the damage early game and that makes him unpredictable. So it's up to you, if you want to be passive or aggressive. His 2 CC abilities facilitate his jungler's ganks, so don't be afraid to call for a gank a few times when laning.

Again, his 2 CC abilities make his roams have a higher possibility of success. Also, Teleport gives Cho'Gath good map presence, especially in bot lane. Bot lane ganks get the ADC rolling and we all know what a good ADC can do when it's ahead.

Since you're the tank, you are in the front line of the battle. Chain CC as many targets as possible and try to absorb the damage instead of your teammates. Try splitting apart the enemy team by attacking the AD or the AP carry. Always look where your carries are and protect them at all cost. Use your ultimate either in the beginning of the team fight on the AD or the AP carry to scare them or to finish off an enemy. With Thornmail, shutting down the ad carry is much easier. With Guardian Angel you can survive burst damage although the tank meta counters burst champions. Cho'Gath is an incredibly good team fight champion if played correctly.

CC, Team Fights and Buff Control/Secure, is what Cho'Gath is all about.
Cho'Gath punishes bad positioning and unawareness.



Thanks for reading
my guide.