Hello. This is my first written guide for a hero, This guide is just a Base so far, I won't really go that far In-Depth as I wish for this to be a more Pick-Up and Play guide.
I will however go slightly into the mind set and play style with Caitlyn, and as everyone always says. There are many ways to play a champ blady bla. You've heard it all before, but for me this was the best way to play Caitlyn. Oh and to everyone who goes "Rawr Ashe has more utility" or "If you want a ranged carry pick Tristana" You can keep your comments to yourself. Cause as far as my experience goes Caitlyn kills just about either one of them. (I so far haven't had time to look at all the other guides but from the few I've seen only a couple have the jist of how I play her. as a Side Note as well. I do not have Caitlyn, I switch heroes nearly every day. But when she was new and free I basically played her then and didn't lose one game, And as such I always play with a friend and usually lane with him. Just as a side note.)

*COMING SOON*


*ADDED*
V2-Added a couple of item discussions

V1,5-Reason behind Why not take the ultimate at level 6 and some tips if you do.

V1:-Added icons (Thanks to ShadowReign757 for the info)

V0:-Wrote the guide :D

Pros:
-Very good damage.
-RANGE (<- This is why you're playing her)
-
-Can be the Whole AD damage of the team
-Amazing passive

Cons:
-Skills go weak late game
-You need bushes for early game
-You'll probably get shouted at for KSing. Or not going in. Stuff like that

Middle of the road stuff:
-She has skill shots, Why is this not a Pro or a Con you ask? Well if you're like me, and a few other people. You're skill shots might hit once in a blue moon, While they can score you some pretty sweet kills, Caitlyns main skill shot has a wind up time, making it Very, Easy, to Dodge, and while early game your skills are pretty beast, Later they'll shy off. Call it a Pro. Call it a Con. That's your choice, The play style section has my opinion on how and when to use them.

-Her ultimate. This has caused people to Rage quit. And caused you to bash your head on your keyboard. Assuming you've already played her you'll know all about it. Why I put this in the middle of the road? Well to me her ultimate Sucks. I mean, I've never killed someone with it at level 6. Granted I only got it for 2 games at level 6 then decided not to take it, but still. To me, her ultimate isn't anything more then a bit of extra damage to an already dying hero. Or a last hit on a running one, and while the latter seems pretty good, most of the time it won't happen.

-She's squishy. We all know this, the only problem is How you utilize this. Many people complain that Ashe is better, or Tristana. and I've played both, my caitlyn build actually was my ashe build and I've almost never died with caitlyn. As for Ashe and Tristana... well... As you can see my build Barley helps her squishy-ness. But with her range and speed, and her Slightly escape. You shouldn't need it. More on this later.

Read this before going any further

Part 1:- The idea of an ultimate
In League of Legends, and in fact it's other games (Heroes of Newearth and Defence of the Ancients) The ultimate is an ability used to change the tide of battle, Your "Ace in the hole" as it were. Ultimates usually come in the form of a Stun, Knockback, Invulnerability, Protection, Healing, Other Utility(Like teleport, etc.) or very high damage.
So why not take it as soon as you can? Well sometimes the ultimate at the current level of play. (Usually the first time you can get it. level 6) Isn't as good as some of your other skills at that moment, and if you would have chosen to level your skills, you may end up dealing more damage because of it. And therefore your ultimate actually hinders you insted of helping. A good example of this on HoN and DoTa is Bristleback(Armadon). You don't get his ultimate untill levels 10/11 because his other 2 skills are much more useful. Important, at that stage. This is also the case with Caitlyn. And here's why.

Part 2:- Ultimate explanations
Part of my reasoning for not liking Caitlyn's ultimate early game is because of the low damage output and the near-to none utility of it, and to present my case. Lets look at some other ultimates.

Teleporters(Or Dashers) - Heroes that fall in this section have a slightly Low CD, Low Damage, or High Cd, Normal Damage/Good utility/Both ultimate. (For Example:- Akali, Kassadin, Twisted Fate, Nocturne, Pantheon, Urgot, Jarven, and Shen. (Fiddle can also slightly fall into here.))

Healers/Buffers/Support - This is the section of ultimates that help the team in various ways. Map Wide heals. Revives, Attack/Movement speed. Invulnerability. If there's something that could push the edge in your favou., these are the ultimates that can do it. (For Example:- Soraka, Janna, Sivir, Maokai, Kayle, Taric, Zilean)

Crowd Control - These ultimates make you rage when they're chained. And You can see why. From whole team lockdowns to Single Target stuns, These ultimates help your team get away, or get the kill. (Ashe, Sona, Malzahar, Warwick,)

Now. There are a lot more types, and I could go through them. But I think you've gotten the point. Everyone's ultimate is useful to the team, In some way or another. Be it mundo and his HP regen. Or Ashe and her arrow. They have some utility other then Just getting a kill. Caitlyn's ultimate falls into the Type of Last Hitter/Big damage. It's the ultimate that'll get that Heroes who got away with 1 hp, or Hit that squishy DPS at the back and scare the hell out of him.
So why do I think this is bad(At level 6)? Next section :D

Part 3:- Math :D
The main reason I think Caitlyn's ultimate is pretty useless at level 6, Is because you don't have the damage to support it. All of the damage ultimates you get at level 6 have some kind of utility other then just pure damage, And the ones that don't can either be fired across map or can hit multiple times. Caitlyn's does not. It does however provide you Sight, and a projectile that will follow them. But when the projectile doesn't do that much damage, and can be blocked. you have a serious problem. Lets look at some math shall we.

Caitlyn. With my setup at level 6, Only counting with 2 Doran's Blades. Caitlyns Damage is 91. her Q is level 3. and for sakes. her ultimate trap and net are all level 1.

(This math is just literal. No Armor/Magic resist will be taken into account)
Her Q hits for 110 + (91 x 1.3 = 118,3) = 228.3 damage. Its CD is 8 seconds.
Her W deals 80 damage over 1.5 seconds.
Her E Slows for 50% for 1 second and hits 80 damage
Her R hits for 250 + (91 x 2 = 182) = 432. Its CD is 90 seconds.

Now her Q has an 8 second Cd. and 2 of her Q's do the same damage as her R. Normally this wouldn't matter but as her R is a 90 second CD for a 450 damage burst at level 6. that can be blocked..... This is the main reason why I don't take it.

Part 4:- Assumptions
So without taking anything into account. Her ultimate looks pretty beast. Here's where it starts to fall off. With caitlyn you're main priority is DPS. And most of her abilitys are tailored to allow you to do it. Traps stunning, Nets slowing. Low CD Q. It's made for DPS. Her ultimate on the other hand is made for Burst. or Last hitting,Lets say for instance you fight with your lane enemy. Lets say Ashe. Purely 1 on 1.
Now say she stepped on your Trap. You decide to go for it , You Pilfer her. and net in + exhaust. In these few seconds you could get off maybe 3/4 auto attacks (Taking in to account ghost and your ghost). Depending on Bushes and Headshot it's around 400/450 with auto attacks and 228 on Pilfer. Not a bad amount of damage. So you go to ultimate her. Here's where I think the utility falls off. If it's purely 1 on 1. She could turn around and Ultimate you before you have a chance to fire it, If not, you get a kill. Good ey?
Now in a real situation, you won't just have 1 on 1's. By the time Ashe was running, You could assume her team mates were coming to her rescue. You line up to fire your ultimate and suddenly warwick pops out and ultis you. followed by another team member, you get exhausted. die. All because you took the time to fire the ultimate. This is assuming a lot. So the more likely one is Someone steps in the path of your ultimate. So you see. You could have taken an extra point in your Net. it lowers the Cooldown, it could have helped you escape. You could have taken an extra point in Traps. It'd give you a little more damage. But taking your ultimate for the off chance that No ones around. No ones going to block it. and that it might get the kill... there's just no point. it's much more viable to get it at level 10/11.

Part 5:-Still taking the ultimate at level 6
Now even after all this, people still feel comfortable, feel it's still vital with taking the ultimate at level 6. And I can't change that, everyone has their own opinion, just as I have mine about the ultimate. But if you do take it please take this into consideration

The 450 damage could be used to start a gank. It's alot of damage to start with, and none of it will be wasted on an attempt to last hit. If there's an Ashe mid, And your Twisted Fate needs help. Run up river and aim it at her. Make sure twisted knows to Ulti in and Card her. that 450 burst damage, plus his stun and his damage, might just be the difference from getting a kill. and Twisted fate dying again.

Your ultimate scares people. Use this to your advantage, Usually enemies are driven when going for a tower dive, so using it on them won't really push them back. But imagine 2 heroes jump your lane mate while your just coming back. Fireing your ultimate at the squishier one will atleast result in one of them getting scared, and that might just save your lane mate.

Part 6:- Conclusion
Really. It's up to you if you take her ultimate or not, it CAN be useful in a certain way. But you'll only ever want to use it to last hit people who are running, in my opinion it isn't worth it until later on when you have your cleaver. Choice is yours.

For runes I run a pretty standard setup, Only not having CD reduction and having Attack speed.
Runes don't really make this hero spectacular and you can play her without them, My personal rune setup was(because I was missing Glyphs)
9x Greater Mark of Desolation Greater Mark of Desolation
9x Greater Seal of Clarity
2x Greater Quintessence of Desolation Greater Quintessence of Desolation and 1x Greater Quintessence of Furor.

This was what I had and did fairly well. An optimal build (In my opinion) might look something like this
9x Greater mark of desolation Greater Mark of Desolation
9x Greater Seal of Clarity
9x Greater Glyph of Alacrity
3x Greater Quintessence of Desolation Greater Quintessence of Desolation

Not much to say here, The only thing worth noting is not getting the magic pen mastery
It's a usual 21/0/9 build with a little twist. a very little twist. I wouldn't really recommend utility past quickness due to the fact that you don't really need CD reduction. and Summoner spells are there to help. Not to get you kills because you can't kill people without them :D

Oh and as for defensive... Haha.. funny..

As for Summoner Spells. My personal picks are and or and . Mainly because I lane with a friend and he runs exhaust too. I prefer if not just to run away, but flash has netted me some kills so. also gets an honorable mention because it works well with when you get your items, and saves you losing exp. Use what you will, just don't take please... or (Unless you're all taking smite to own :D)

Also, pretty standard. You can see it all up top, the "Priority" if you can call it that is Q > W > E. Taking her ultimate at 10/11 and 16, and with 1 point in E to start with or at level 2, but you really can't go wrong with Caitlyn.

Ah the items. The main reason you came here. As you can see it's probably not the usual Caitlyn build. Or if it is, I don't see it ranked 1 on this site :D.

Core:3x , 1x , 1x .

You start off with a . Simple huh?
Then when you can buy 2 more, blue pill back.

Why 2 more you ask?
Well 1 has never served me well. is much better if only because it's constant HP regen rather then lifesteal. And if you do get pushed back to your tower, you won't be getting life back. So I decided to get 2 more. When you have 3 you get 9% lifesteal, 300 hp and 27 damage.
Honestly this part's not too flexible, some people like 2. Some only 1. But please try at least 3, because unless you get fed like hell and can buy your next 2 items already then you're basically invincible anyway. They don't build into anything, but they're like bracers or wraith bands in DoTa.

After that get your (Note:If you do not feel pressured on your lane or are in need of dodging skill shots please feel free to buy before a 3rd

After that you'll want a . I personally see its change as a buff, and Attack speed + Damage is exactly what you need.

To me this core will serve you well. From here it's slightly optional. Don't worry if you can't make it up as you go along, following the build up top will be fine. But from here you need to assess the situation.

Semi-Core: . This will be mentioned as a Semi-Core. Because it's exactly what you want. Crits, Damage. You can't go wrong with this.

Option 1: - This is for the teams where they have some fast heroes, heroes that can close the distance pretty fast, heroes that can keep you next to them. This is bad for Caitlyn, So gives you a slight HP boots to cope with the damage you may take. and a Slow to get away. combined with your Net you shouldn't have much trouble

Option 2: - This is the one you'll usually go for, More crits, More movement speed, More attack speed. Need I say more?

Option 3: - Sometimes, an isn't what you need. Maybe they have..... Something? I'm honestly not too sure why you might get this. I usually get it after all my other items, sooner of later you'll end up with all of them anyway, The 1 thing I will mention is that if you want it because of the lifesteal, just buy a scepter instead and build another option.

Final Build:

Selling the : I doubt this is really needed. But in case anyone wonders when to sell them, just sell them when you need space for that next item, it's usually better to only sell 1 at a time as opposed to 2. but if you're going for a frozen mallet and want life steal feel free to sell 2 and buy a in the meantime.

I was playing a game today, and I finally saw someone playing Caitlyn. as the game went on though, with her being 1/8/3 if I remember correctly, I wondered why she had this score. After actually getting first blood. So after a quick look at her items or Rather her first item, I could see why. So I thought to myself that maybe other might like to see an opinion on why I get , and my other Core first.

The stacking:-
I feel this part wasn't explained to its fullest. So lets have another look. On the surface not many people like to buy more then 1 doran's item. And you can see why, it doesn't build into anything, it delays your build, and if you don't have teleport they can as well delay your experience. The first thing I'd like to disregard is the fact that it delays your build. We all know this is true, but I find not getting an extra 2 early on makes me miss out on some kills, 2 extra dorans blade is 950 gold. And people do see this as a big chunk of your B.F Sword, but I prefer getting the extra 18 damage, 200 hp and 6% life steal. If only because it's still early game, early game for caitlyn is quite an easy one, but she Will take some damage, having enough hp and lifesteal to shrugh it off, with the extra bit of damage to push them back again is what keeps you alive. And keeps you on top. say for instance I had attempted to rush a B.F Sword, and now for sakes say I've stole all the minions in my lane and not let my partner have any, By the time you're six you would be Near. but not that near a B.F sword. and this is usually the point in the game where you die, When that tryndamere gets his ulti. When Ashe has her arrow. So my build tried to work around this by keeping you in control of the lane with a couple extra "Bracer's". I could bang on about this all day but it probably wouldn't change your mind, try it. See how it goes, what have you got to loose? 1 game?

Now on to the real part of this guide, other item choices. (Note:- When I talk about these items I'm only talking about there usefulness as a First item after your Blades and Boots. Not as an item on the scale of the whole game, end game, or anywhere in between.)

:- I find this item to be the best, of the best, for your core build after boots. It gives you Attack speed, Damage, and a debuff to Armor every hit. It was either this or an infinity edge, and I'll be honest I do like this, it gives you an extra bit of attack speed, and a good stacking debuff, Sure Infinity Edge is great, Thats why I suggest you get it next :), but in my tests I feel that TBC is alot more viable at this stage of the game

:- If you did pick this up instead of TBC, You'll probably want a Zeal next, Your crits are good, but the chance is still a bit low, You're damage is great. but your attack speed lacking. I think this item as a first is not as good as TBC. It's still very good, But just not As good at this stage in the game, still I doubt it'd change the outcome of the match That much. maybe just your score slightly.

:- No, no, no, no, no, no, no. I've seem a few caitlyn's try this item on for size after getting their 1 doran's blade and boots. And let me tell you. they're usually the ones with the negative score, Madred's isn't a bad item, on the surface. You'll be sure to kill an enemy hero every 25 hits you do on him, regardless of HP. But honestly... It has 30 attack damage, 40 speed and 35 armor, Your skills are only useful early game, and they are pretty freaking awesome, and do a lot of damage, so why oh why would you get this item, nearly 4k gold to complete it. and it only gives you 30 damage.. Sure the attack speeds nice, but thats why you get Greaves and TBC. Sure the passive is nice, But why would you care about killing someone in 25 hits, when your main target, for now, is squishys. Bad item choice for this stage of the game, Very bad.

:- This is another one of those, Doesn't seem to bad but it is, kind of items. for 2290 gold you'll get 40 attack damage and 40% armor pen... Yay? At this stage of the game no tank will have enough armor to even justify getting this, and if they do... you've had some Bad feeders. sure the damage isn't bad, and you can use the 40% armor pen later. but you can get a B.F Sword for 1850, and it does more damage, so it's kinda a no brainer here.

Now that the boring stuff is out of the way, onto the Important stuff, notice IMPORTANT. :D

For laning you'll want to take either Bottom or Top. Why not mid you ask? Caitlyn, in my mind, has never really struck me as an amazing mid hero. Sure she has range, and damage. But to be useful she needs the bushes. You have to use them bushes like it's the only place you can move in the lane without dying! Kinda... So yes, Bottom or Top, unless you don't have a mid hero, but really anyone is better then you

Once you get to your lane, lane mate in tow (Just hope he knows what he's doing to). Go into your bushes. I cannot stress this enough Caitlyn excels here because of her passive, I haven't said much about it so far, but the reason is this is the place it's useful. The lane.
Her passive, as you know, gives your attack a "headshot" if you will, and the counter fills up by 2 each time if you're in the bushes. You should rarely leave the bushes, if only to get a kill or harras with your Q.

So, You're waiting in your side of the bushes, the minions spawn. and suddenly you see mundos cleaver popping through the bushes with his ugly face behind it. What do you do? Well you have to think fast, if you're team mate can handle this (For instance mine is usually a trynd) and you are CERTAIN that there is no other scary heroes that could kill you in around about a second. Feel free to duke it out. You have exhaust, and if your team mate does this means a lot of head shots, usually you'll come out on top. The other option is to run, and this is also viable. Just remember you need those bushes to do something.

The main difference I've seen with caitlyns and how I play her, is the Headshot. Most caitlyns will shoot minions until getting it and then shoot a hero, or save it or something. No, this is predictable. Anyone can see this, The way I do it, the way To do it. Is to sit in the bushes pushing your lane, that's right, auto attack those minions. Do not save your headshot, Forget it's there if you like. and as soon as a hero gets in range, (You'll be wanting to stand inbetween their ranged creeps and their tower so you can zone them) Shoot him. If he runs towards you, he'll probably die because your lane mate and you can take him, if he runs back he'll lose Exp. Job done.

Once your lane is pushed to their tower, attempt to land a Skill shot(your Q) It has a good range and does a lot of damage, Feel free to use your skill shot when ever you feel the need. The auto attacks are a good Mind play on them, if you just keep hitting minions they'll get used to the fact when they come near you'll shoot them. This makes them easy targets, just try to do it from the bushes, her wind up time is awful :(.

That is basically the laning phase. Don't forget to put a trap in the bushes river side and a few in your side. (Note: If they had a jungler. Mainly warwick. Your traps Can cancel his ultimate if you're lucky enough. Just put one down when you think he'll jump you. This has saved me many times)

Now onto Play style. Your Play style won't change to much as the game goes on. But the one main thing that will change will be your Use of Skills. or rather Lack of Use. As the game tolls on, your skills (Q to be exact) get weaker. And waste time. So try not to use your Q unless you're shooting into the Fog for a last hit. Your main source of Damage is your auto attacks, Auto attack away. and Aim for people IN YOUR RANGE. This might come as a shock but I'm not telling you to Focus anyone. Caitlyn survives because of her range, your job is to be at the BAAAAAAACK of the team fight. at the Back of your team, away from all the damage. auto attacking your way. if a hero starts to charge you, don't be afraid to fire your E at him to slow him down. usually you're team and you will kill him before he gets to you, but don't forget to kite. I cannot stress this part enough Also. Many people with caitlyn go straight for squishys. and they'll usually get a kill.. they'll also die. Any hero like Kassadin or Tristana will get a shot to the face if they try to jump you in a team fight. So just pelt the tank, pelt who ever you can hit, But lay traps to be useful.

That's basically it. My whole guide revolves around these 2 things. Bushes (For the Start) and Auto attacks(Defensively). Try it out, it makes for some interesting play tactics.

Caitlyn is a fun hero, I'd much rather play her over say Tristana or Ashe. But times may change, she may get nerfed or buffed. This is just my way to play her, and it works for me. I can't make magic happen if this doesn't work for you. It might just not be your thing, and if it isn't don't fret. There's always more heroes :D

Peace

I've just added this to see if it fixes my current publishing issues. I do hope it works.