For starters, the title isn't good at all. What's up with putting Tristana in the title? I wasn't sure if it was a corki guide or a tristana guide.
Also, you have 0 BBcoding. Look up Jhoijhois guide on making a guide so your guide looks decent instead of just walls of text.
For "hard to lane against" you put every single ADC then explained how they're all cakewalks.
There's also tons of grammar errors that makes it seem like you put in the bare minimum effort. I would probably do a major grammar sweep

Im not very good at ADC, but your guide looks very good :)

A couple of suggestions though (I wont talk about items because Maintained already did).

I don't undersand the title, why would you put a Tristana quote on a Corki guide? (and put her name on it, if taking a unrelated quote wasn't enough).

Your guide hurts my eyes :O
You have very little BBCoding (If not none). Its just WALLS and WALLS and WALLS of text. I only read those on books, not on a MobaFire Guide ;)
Take a look at jhoijhoi's guide on making a guide, it will improve yours a lot (My guess is that probaly 90% of the people that made a guide has read it).

I'll hold my vote :) (For now :P)

Keep at it!

Hey thanks for the advice man! I never thought about some of the things you said (i made this build on the fly in the morning!)

I'll fix some of the things you mentioned in the morning, i appreciate you taking time out of your day to take a look at my guide and posting feedback :)

Let us talk about your cheat sheet;

• 2x Greater Quintessence of Life Steal + 1x Greater Quintessence of Attack Damage is in general better than 3x Greater Quintessence of Life Steal.
• Trinity Force should be your only attack speed item. Replace Statikk Shiv with a defensive item.
• Black Cleaver is a good option on Corki, as an alternative to Last Whisper, good catch. But your explanation to it wasn't great. You need to explain that he can add stacks very quickly.
• Sometimes Sorcerer's Shoes make a better option than Berserker's Greaves, due to the fact that all his poke is magic damage, and he isn't as AA reliant as other carries. You may want to implement that.
• Cheat sheet lacks defensive items.
• Expose Weakness is very weak on Corki. You should be the one dishing out damage, not asking your team to do it for you.
• You went a little over with taking 5x Health Potion on your first back in my opinion.

Good luck with the guide!