Hey people,

ive played Caitlyn for a few times now. Caitlyn is one of the best carrys in the whole game, because she has a huge range, 90 Caliber Net to chase/escape from enemies, can snipe enemys that run away with your Ace in the Hole and can steal buffs, dragons or baron with her Piltover Peacemaker (if the enemy team doesnt manage to smite it and you time your spell well). You can also cover a small area of your lane with your Yordle Snap Trap.
Dont lynch me for my english thx :P

Pros:
-High Damage output
-Highest auto attack range ingame (except lvl 18 tristana)
-Great escape and farming abilities

Cons:
-Squishy
-Can be killed with ease, if getting focused and your team has not got enough cc to protect you
-Squishy
-Did I mention you are squishy?

I use 21/0/9 as my masteries for maxed damage and exp. You can also use 9/0/21 to max out your movement speed and buff duration. The reduced cooldown and the manareg is nice too. Then you should grab Deadliness , Cripple, Alacrity and 1 point Sunder in offense. You dont need Archaic Knowledge and Sorcery not as much as you need your Alacrity and Sunder .

But lets take a deeper look at the 21/0/9 Masteries. Why shouldnt we grab Archaic Knowledge ? Your main damage skills are your Piltover Peacemaker and Ace in the Hole. Both deal physical damage. You dont need to boost your magicpen, as long, as you dont want to troll ap Caitlyn. Alacrity and Sunder are more useful than Archaic Knowledge . Brute Force is always nice, not to mention Lethality . Havoc will rape your enemies, so be sure to skill it.

Allright for marks you have 2 options. You can take greater mark of desolation or Greater Mark of Attack Speed. BUT the atk speed wont stack with your peacemaker the armor penetration does. The only profit of using the atk speed runes, is to take advantage of Headshot more often and lasthit easier. Its also useful to take enemy towers down faster. Note: its also possible to take flat ad runes, but in general you should always pick greater mark of desolation for ad carrys.

Why do i grab Greater Seal of Attack Damage? They stack with your Piltover Peacemaker, your autoattacks, your Headshot and your Ace in the Hole. Any questions? Of course you can grab Greater Seal of Critical Chance to surprise your enemy or grab atk speed runes to Headshot more often, but with Greater Seal of Attack Damage you dont need to hope for critical strikes.
You can add defensive runes here. Greater Seal of Armor help you to survive longer, but im not a fan of it, because it wont grant you much more early game domination. If you think of someone with full armor pen runes, he can completely ignore your armor even with the runes. With masteries he will have got 31 armorpen. So with armor seals you will get out of 0 armor vs the enemys auto attacks after a few level ups, but i still prefer to grab Greater Seal of Attack Damage.

Why should we grab atk speed glyphs? They grant you a nice atk speed boost and they also grant the best bonus for auto attacks if you only check the glyphs. Crit damage or chance are also an option but im not a fan of it. You want to grab cd-reduction? Sure do it but you shouldnt rely on your skills too much.

Allright now we got 3 otions for quintessences, which i prefer.
1. Flat Damage: Boost on your auto attacks, your Peacemaker and the Ace in the Hole.
2. Armor Penetration: Same as Flat Damage, but grants you less early game domination, because only a few characters actually posess enough armor to face your marks and masteries.
3. Flat Health: If you feel you die too fast, you can grab them. But if you eat too much damage then you or your Support are doing something terribly wrong.

Allright the most important thing you need to know about caitlyns skill sequence is this: It rly depends on your lanepartner! If you got someone with hard cc you should choose Piltover Peacemaker to ensure you can use the time the enemy is cc'ed for max damage. If your lane partner has no hard cc, but damage, you can choose your Yordle Snap Trap first and hope that the enemy is stupid enough to run into it or facecheck your brush. After that you should skill Piltover Peacemaker. You can grab your 90 Caliber Net, if you fear to get ganked, but i like to deal max damage all the time.

You can max your 90 Caliber Net after Piltover Peacemaker for more slow and damage, when you try to escape, but im more a fan of dealing more damage, if an enemy accidentally steps on your trap. The lower cooldown is also nice.

Recommended:
: best escape skill ingame! Also your flash in combination with your net can save you out of nearly every situation (if used right). Example: net / flash over a wall in the jungle and use the other skill to get over the next one.

: Lowers the enemys damage, movement speed, atk speed, armor and mres. What do you need more?

Viable Options:

: Rly a viable option, but flash always goes first. You can pick it instead of exhaust if another member in your team has got exhaust (you should always have got one exhaust in your team).

: Useful to pick up kills, but you dont rly need it with your range. DO NEVER PLAY CAITLYN WITHOUT FLASH!

: If you get picked up by stunlocks very often you can take this skill, but with your range you shouldnt get stunlocked until you are careless.

: Useful to push/farm/def/get back on your lane. Still i prefer to take a skill with in fight efficiency.

: Allright if you spam your skills and often got no mana to snipe the enemy champ you can grab it. But im not a fan of it, because youre not THAT relient on your mana. You still got your auto attacks and can flash out of range if needed. Exh. can save your butt or let you kill the enemy too. So i dont think its needed.

: Until you want to jungle (YOU SHOULDNT!) you shouldnt grab it.

Clearvoyance: Grab it if people often escape out of your sight and your supporter is too dumb, to take clearvoyance or use it in that kind of situation. You can also use it to cover yourself from getting ganked or to snipe someone behind his turret. Still thats the job of the supporter. Let him do his Job.

: Pick it if you want, but i'd even recommend to take smite to farm/jungle/steal buffs and barons before recommending to take heal!

: You're serious?

Dorans Blade: Bonus damage, lifesteal and health. Thats all you need as Caitlyn.
Grab Boots and a second Dorans to get more survivability, sustainability and Damage.
Upgrade your Boots: There are a few options here: Berserker Boots for more Domination, Mercury's Treads if the enemy team got much Magic damage/cc, Ninja Tabi vs a full ad team and Boots of Swiftness to be very fast!
B.F. Sword: I! NEED! MOAR! DAMAGE!!!
Why grab Zeal before grabbing Infinity Edge? Atk Speed, movement speed to prevent yourself from getting picked up and the crit chance to rly hurt the enemy. If the enemy team cant pick you up anyway build Infinity Edge first.
Grab vampiric ceptre for more sustainability if you feel you need it. I usually grab it to survive teamfights with more ease.
After Building Phantom Dancer the build is your Choice. If you fear the enemy cc for example get picked up by Malzahar or Warwick all the time grab banshees vail.
If all of the enemy Team are building Life as Defense you can grab Madreds Bloodrazer, but im not a fan of it.
Follow my Build for Much Damage, a bit of sustainability and constant slow. If you grab banshees you have two options: drop Frozen Mallet to grab banshess vail or drop another item if you really feel you need that much hp.

Your very best friend is Taric. He casts Dazzle on your enemy, you place your Yordle Snap Trap under the stunned enemy and hit the enemy with autoattacks, Headshot, Piltover Peacemaker and Ace in the Hole if he can escape. Early Game everyone dies to this combo, except a few offtanks. The heal, armor and ad buff, which Taric grants you, is also nice.

Alistar: He is a good friend of you. He can cc all the enemies in his range and even heal you... a bit.

Everyone who can cc your enemy and needs no farm is a good friend of you.

Allright this is my way to play Caitlyn. If you have any queations or tips, pls comment. :)

Just to say it again: Caitlyn is and will hopefully ever be one of the best ad carrys ingame.