Hello, my name is KrnXJunHyung and I'm here to share my ideas for Caitlyn. I got her for free when my friend gave me a code from a magazine he bought for Arctic Warfare Caitlyn, and used her numerous times. She is one of the best carries, and I don't understand why they say she has the worst late game. She keeps her long range pokes, her traps, her escaping net, and the ultimate which is really fun to use especially when you net yourself a kill with it. Satisfaction. Anyways, please read the whole guide and comment/vote to give me some advice.

I use flat AD marks and quints for additional 15 damage. Why not Armor Pen? We end up getting Last Whisper, which gives 40% Armor Pen, and by getting additional flat Armor Pen, it bothers with Last Whisper's mechanic. Flat armor seals are used for that 13 armor which'll allow you to take more harassment from enemy carries, making trade more effective for you. I use attack speed glyphs because with it, I can harass better and get my HeadShot up faster. Magic Resistance per level is also fine, but I tend to go with attack speed.

Okay, now here's how I usually build Caitlyn. First of all, it depends on who I'm laning with. Are you laning with a partner who has sustain? If yes, then grab Doran's Blade. If not, then grab normal boots with 3 potions. On your next return, you'll aim to have 2 dorans and a shoe (or berserker's if you got gold). Double dorans will allow you to have better survivability, more life steal, and 20 more damage. Considering that it only costs 950, I'll take it. It'll allow me to net some early kills to make up the gold anyways. BF Sword comes next, followed by a vampiric scepter. However, you don't build Bloodthirster straight away. You instead aim for Infinity Edge. Why? It gives more damage, and especially with your passive and crit, you will hit like a truck. Phantom Dancer comes next for more crit, attack speed, and movement. Now here's where you make your decision. If 3 of the enemy champion has over 100 armor, grab yourself a Last Whisper right now. If not, grab Bloodthirster first. Then you grab the other. For your last item, it depends on the situation. If you are getting focused, grab more survivability. If you want more damage, build another phantom dancer or a bloodthirster. I build Quicksilver Sash just because of its cleanse(saved my life countless times).

You get W first for traps, in order to make sure enemy jungler doesn't invade. After, you go

R > Q > E > W

I grab Flash and Heal because it allows me to net some early kills with heal bait, and Flash is a must on every ad range. You can grab exhaust, cleanse, or ignite in place of heal.

In a team fight, your job is to stay back and deal damage without dying. If the enemy is smart, they'll jump straight at you. So, stay behind your tanks! Your tanks are there to disrupt enemy and make sure they are not on top of you. Escape with E when someone does manage to get near you, and keep dealing damage.
Your focus:
AD Carry > AP Caster > Support > Bruiser > Tank

I got really bored, so I decided to make my first guide on Mobafire. I know it isn't the best guide, but I'm willing to take some advice into consideration to make this guide better. Thank you for reading this whole guide, and I hope you kick some enemy butts with this build.