Starting with the most crucial section of any guide is the top of the guide. Items, Match-ups and Runes & Summoners. You may have the information in the body text, but for the majority of users, they simply want the straight forward answers at the top, since it is considered the "cheat sheet" in comparison to the rest of the guide.

You can add this information in the "Notes" section at the bottom of the section you're working on. HERE. It may not seem like much, but it does offer the information for the people who simply do not want to read a guides body text.

It's a bunch of different builds rather than a standard build that you have here, but alas there are no (Quick) notes on when or why, the titles leave more information to be desired.

Like, I rarely ever see anything other than Cho'gath Grasp, used to see Comet, but never any other runes, so I'd like to know via notes, why, or just more detail into these things like Hail of Blade Cho'Gath.

What is there to say about this...
The straight up answer is your guide body text is severely lacking. I would highly recommend you take a look at the BBCODE guide or look at JHOIJHOI's Making A Guide, to get a better understanding for structure, format and basic BBCODE usage.

You do have a lot of information in your Match-Up notes which is nice, gives the reader what they want essentially, but as a guide it fails to really grant anything past the cheat-sheet section.

Consider looking around other guides, see what they are doing, contest winners and frequently featured guides are amazing and can help offer you ideas for your body text to improve your guide to stand out more.

It's a very short review because well, there isn't much here to review at this time. I can't really grant a detailed review or say much in terms of giving you any personal advice besides go back to the basics of the guides listed previously to read up on.

A guide should be detailed, neat, visually pleasant to look at with a good use of structure, format, colors etc.

This doesn't really have any of that, just the bare bone minimum text of Pros/Cons (which should be centered not pushed to the side), Abilities and Itemization for 4 items. There has to be more about Cho'gath, videos, gifs, more explanations.

Try to use the tips I recommended. Guides, Browse top guides and use them for your own guide to bring it to life.