This is my guide for playing Caitlyn in ranked games. My ELO is only in the 1600 area so it's obviously not meant for high ELO rape fests. This is how I play her and have had the most success.

This is a build for my personal use. I am not making this as an all inclusive Catilyn guide but I'm publishing it so others can see how I play her. It's a very strong build for Caitlyn.

Standard AD Carry runes. Armor Pen. reds - Mana regen /level yellows - Magic Resist /level blues - either Armor Pen. or Attack Damage Qunits (whichever you prefer).

Standard AD Carry Mastery requiring increased Crit Damage and Havok from Offense tree and buff duration and EXP. increase from utility.

Standard skill sequence. If you want to get your E at level 2 or 3 because your lane is playing very hard against you then definetly do it.

You should always be in bot lane in a ranked match with a good support. Your favorite teammates would be Taric or Soraka. The cobo of Taric stun plus you placing a trap right under the enemy means you will more than likely get a kill. Focus mostly on last hitting every minion. The Wriggle's Lantern comes in very handy for this because it helps you all game with Red, Blue, and Baron buffs. On top of that the lifesteal you'll have from Wriggle's and Bloddthirster means you can go 1v1 with a lot of melee carries.