Caitlyn is a ranged DPS carry suited to both side lanes and the middle lane. Her spells have both offensive and defensive components, and her passive grants an attack bonus if used right. Her early game and late game are both stellar, but her middle game usually seems lacking. Part of this may just be the build, but I also believe it is the design of her character. For those of you new to the game, I would recommend playing Ashe before trying Caitlyn, as Ashe seems to provide better escape mechanisms with her Enchanted Crystal Arrow and her Frost Shot.

Passive: Headshot provides extra damage after a certain number of shots, dealing 150% of Caitlyn's normal damage to enemy champions and 250% to minions and monsters.


First Spell: Caitlyn's Piltover Peacemaker is an aimed shot that deals damage to every minion, monster, and enemy champion in its path. The amount of damage taken decreases based on how many other targets it has hit before making contact with the intended target. To deal maximum damage to the intended target, a clear shot is necessary.


Second Spell: The Yordle Snap Trap is a placed trap that is sprung when an enemy champion steps onto it. The trap deals damage over time, snares the target for a short perod, and grants Caitlyn visibility of the unit. Each trap lasts 3 minutes if not sprung, and only 3 can be placed at any given time.


Third Spell: This spell is usually used as a defensive weapon, allowing Caitlyn to escape from ganks and slow her pursuers. the 90 Caliber Net is an aimed shot that throws Caitlyn the opposite direction of the shot, as well as slowing the first enemy or neutral champion or minion it encounters.


Ultimate: Ace in the Hole is my favorite from all of Caitlyn's spells because it allows the player to assassinate any visible enemy champion in range with low health. For this spell, Caitlyn lines up a shot, dealing massive amounts of damage to the first enemy champion the bullet encounters. Other enemy champions can intercept the bullet to save their teammate.

Since I started playing Caitlyn, there have been two styles of play that tend to suit her quite well, particularly in the early game. Middle and late game, these play styles tend to blur together, as Caitlyn is a ranged DPS carry. During the early game, I usually tend to play an aggressive play style, forcing my enemy back to their turret early and often. This is not a bad idea, as it keeps them from getting as many last hits on the minions early, due to the turret. However, if you are getting beat in the early game, Caitlyn can also be played well with a passive early game, sitting close to your own turret and keeping your enemy back from the minion wave a little by the threat of the turret. Either way, the Piltover Peacemaker is a crucial early game weapon, both for farming minions and for early game harass.

Caitlyn is fairly straightforward to play. Attacking a little more than just to last hit will allow you to use your passive more frequently during early game. Hitting your Piltover Peacemaker and your Headshot almost simultaneoulsy is pretty much an early game nuke for Caitlyn. Caitlyn tends to dominate the early game with her Piltover Peacemaker and her Headshot. Use this to your advantage and force your opponents off lane and keep them from getting farm. Be careful, though, because when this starts happening, ganks start to lean towards your lane. Always be aware of potential ganks and the movement of their jungler.

I may be very wrong about this, and it would not surprise me if I was, but, for the most part, the middle game with ranged DPS carries seems to go very badly. Either they do not have the right items, or they do not have as many items as they would need to carry the team. This might also just be the way I build my champions; I just do not seem to have the damage output and damage per second necessary for the early ganking phase. Use these ganks to your advantage and make sure to deal damage to multiple targets, as if you do not get the kill, you can get money for the assists. Do not waste your Ace in the Hole, as you will wish you had it, come the end of each of the team fights. Also, when you get the chance, run around and place your Yordle Snap Trap in random patches of grass where enemies are likely to camp.

This is your time to shine. Your damge output will be high, your attack speed up, and everyone will love you. You will wind up KSing a bunch because you can't help but eliminate targets too quickly. During team fights, focus on their damage dealers, particularly those with range. Your range is longer than most, so use that to your advantage and do not forget to spam your Piltover Peacemaker. Make sure you keep enough mana to use your Ace in the Hole, but otherwise have at them.

The Masteries:
The masteries are completely up to personal choices. I would recommend these masteries because Caitlyn is based completely off of damage. These masteries increase the damage output, attack speed, armor penetration, and grant a very small amount of lifesteal. The defensive masteries can get you back on lane faster and support the summoner spells.

Runes:
These runes on the first build are all attack speed, which boosts Caitlyn's attack speed to almost one attack per second to start. If you choose to take different runes, such as I exemplified in the second build, I would recommend moving the Zeal to just after the Berserker's Greaves in order to grant the extra attack speed. As for the second build, these are just runes that I would probably take.

Summoner Spells:
I have chosen these summoner spells for several reasons. Usually, I take Heal and Clarity with DPS carries, particularly with Ashe and Vayne, but the Vampiric Scepter grants Caitlyn enought lane sustainability to avoid taking Heal. I no longer take Claritywith Caitlyn, but be very careful with your mana, as Caitlyn can be very mana hungry, especially when using her Yordle Snap Trap and Piltover Peacemaker often. I have since changed from Teleport to Exhaust, which is much better for an AD carry, especially one that has an escape built in. If you choose to change these, just make sure to take the mastery points that support them.

Starting with a Vampiric Scepter is a good option, as it gives lane sustainability and allows you to stand and fight enemy champions without needing to back down. After the scepter, Boots built into Berserker's Greaves increases your attack speed quite well. After this, always prioritize damage over attack speed, critical chance, etc. with the exception of Zeal. This is about all you will get for some time, as you need to save for your first B. F. Sword. Build this into a Black Cleaver, as it will boost your attack speed and allow you to dominate enemy champions with its armor reduction. After that, build another B. F. Sword and a Pickaxe, followed by a Cloak of Agility to build an Infinity Edge. A third B. F. Sword will combine with your Vampiric Scepter to create Bloodthirster. At this point, your damage will be high, but you will not have enough armor penetration to do much damage. Building a Last Whisper from a Pickaxe will help immensely. Finishing with a Zeal built into a Trinity Force will boost your attack speed a little more and add more damage.

Take this skill at levels 1, 3, 5, 7, and 9. It makes for incredible early game harass and can keep enemies off of the minions. Also, I have encountered people stupid enough to recall by their turret during the laning phase. You can't do that against Caitlyn as her Piltover Peacemaker can leave you dead instead of back on your summoner platform.


Take this skill at levels 2, 8, 10, 12, and 13. The early game trap can deal quite a bit of damage, but is better used to do two things. In outside lanes, the use of the traps can cut off the grass from the opposing side and can guard against ganks when put in that patch of grass towards mid. In general, just use it to restrict you enemies' movement in the lane. In middle lane, use it to guard against ganks by putting the traps in the grass on either side of the lane. I have been saved from ganks several times over by these traps being set off and giving me visibility of the enemy champion set to gank.


Take this skill at levels 4, 14, 15, 17, and 18. The early net is used as an escape mechanism throughout the entire game. It can be used to slow an escaping enemy, but I don't put much stock in it. To be completely honest, this spell is next to pointless beyond the first level. Use it to escape ganks and lost teamfights. NOTE Caitlyn's 90 Caliber Net can be used to push her over walls.


Take this skill when possible, at levels 6, 11, and 16. The idea behind this skill is great, but actually implementing it takes practice and quite a bit of luck. This shot takes about 2 seconds to shoot and deals massive damage to the first enemy champion it encounters. If all else fails, it will hit your intended target, usually killing them. This works great at level 6 when used in a combo with your Piltover Peacemaker on a low health target. The peacemaker will get them down to a low enough health that your ult will kill them.

spaaaaaaaaaaaaaace

Pros + Armor shred + Good early game harass + Massive amounts of damage + Fed Caitlyn=win + Ace in the Hole + Escape mechanism

space

space

Cons - Squishy early game - Incredibly expensive build - Singled out as the DPS carry - Early game farm dependent - Not farmed=big problem - Ace in the Hole can be blocked

Early Game

Farm up. You need everything you can get. Last hit EVERYTHING and keep their carry off the minions if possible. It is OK if you don't get every last hit, but make sure you get most of them. Sacrificing one last hit to throw a harass shot with your Piltover Peacemaker is OK. At this point, all you are trying to do is to get fed and keep them from getting fed.

Middle Game

This can be debated several ways. In general you have three options to keep sustaining your farm:
1) Set up and participate in ganks - this can be somewhat difficult, as you have no CC

2) Join in ganks and teamfights outside of your lane - use Teleport to get there

3) Stay in lane and farm - my preferred option, as I am guaranteed farm and an easy escape
No matter what you do, make sure not to feed their carry at all.

Late Game
Gank and teamfight your a** off. You have damage and attack speed. You have armor penetration. You are the reason your team will win. You should be 2nd in and stay in for the entire fight, if you can survive. If things collapse, get out, as your team needs you alive. Take kills, use your skills, and don't be afraid to (don't make it blatant) KS.

Masteries
Since Caitlyn is mainly a DPS carry, offensive masteries are the best option. The extra attack speed and damage are helpful, particularly in the early game, when you do not have much health or damage output. There are other spells in the utility column because there is no other true place to put them. The improved recall is not necessary at all, nor is the difference in death time. These are just to waste extra points. However, the rest of the points are used in improving my summoner spells.

Summoner Spells
I particularly chose Exhaust and Ignite because my particular style of play tends to be very aggressive early on. This combination can usually secure a kill when done right.
Other recommended spells are:
Flash - Good both offensively and defensively
Heal - Not really necessary, but nice
Cleanse - For that pesky tank crowd control
Surge - Great for extra DPS
Ghost - Offensive use: yes, defensive use:NO
Bad spells are:
Rally - Really?
Clairvoyance - You have teammates for a reason
Fortify - NO
Promote - What are you thinking?
Revive - How crazy can you get?

Caitlyn: Nuff said

Brand: Don't try it. Once he hits level 6, his burst damage will ROCK your s***

Ashe: Great matchup for you. You have a longer range and more early game burst damage.

Ezreal: I can see this falling either way. It depends on playing styles and skill levels.

Tristana: Same as above. I can see this going either way.

Malzahar: WIN! He has no damage output if you can keep him controlled early.

Poppy: This is an unusual mid, but don't try it. She does too much damage.

Teemo: This could go either way. Usually it will go badly for you with his blinding shot.

Ryze: Keep him controlled early and you win. Lose it early and it's over for you.

Annie: Same as above. Keep her controlled.

Cassiopeia: This is an easy win for you. Her spells are mostly AoE spells.

Corki: I haven't seen a Corki-Caitlyn matchup mid, so I can't exactly judge this.

Kennen: You will probably lose this, but you can give it a shot.

LeBlanc: A good one will kick your a** with their burst damage. A bad one will feed you.

Miss Fortune: I haven't seen this, but I'm pretty certain that you would win.

Lux: You win. No contest.

Morgana: So long as you have a Vampiric Scepter you can outlast her mana.

Nidalee: Her spear is her only real damage output. Just don't waste your mana.

Swain: I can't seem to beat him mid. It might just be my inexperience, but I'm not sure.

Sivir: With the patch, watch out for her extended blade, but if you dodge that you win.

Urgot: Watch for those little poison canisters. A bad one, you win. A good one, you lose.

Vayne: Same as above. It all depends on playing style.

Xerath: No zoning control. You win.

Vladimir: You will win this, but it will be hard fought. Don't let him get fed.

Twitch: Twitch mid? On lane, you lose instantly. In mid, barricade yourself back.

Twisted Fate: I have not yet seen post-patch TF. However, I think you would win.

I welcome the challenge of answering your questions as completely as possible. Also, please post your variations. I will try to get around to answering as many questions as possible and if there are enough suggested variations, I will add another section for posted variations. As such, this guide is as complete as it will be for some time unless someone can tell me how to get replays from LoLReplay and the KDR page from the summoner profiles onto here.