Of my experience play Caitlyn, she's one os the strongest carries you will find. She does amazing dmg, and she can harass amazingly with her headshot, which can be used after every 7th shot. This is how I play caitlyn, and I want you guys to see how I do.

I love having these runes. She is quite squishy in the start, which makes the health runes (imo) quite usefull. I know some armor penetration is very usefull, but I just find having that little amount of health more a game change (also late game its nice).

The masteries are mostly defense because she's squishy as ****.

I love this final build, because with headshot she can crit upto 2000. It is truly amazing. You can consider swapping a bloodthirster out for some armor or hp, whatever pleases you, but you need everything else.

farm as much as you can early game. it is the most essential thing to late game. fail at farming and you will fail caitlyn. unless the other team is handing you out all the kills you want ;)

Exhaust i find usefull, example if you wanna engage a stronger opponents than yourself, you will find it VERY usefull.

Well, max your Q and W and you will be fine I suppose. Q does massive dmg in the start, but dont spam it cause later you need the mana.