RF is good 1st due to the fact it gives you a ranged attack and cleave. but kayle's true power lies in her other abilities. Dorans gives armor and life regen as well as life allowing you to stand back and farm and not be bothered. once you get your greaves and cutlass you now have damage attackspeed and 2 slows. The guinsoo will help get you kills after you have the Hextech finished. The trinity force is the ultimate hybrid item. It gives you everything. once you have the trinity, guinsoo, hextech you have endless possibilities. I chose Lich bane for mana magic resist and the Trinity Lichbane damage stack for one hell of a punch. Then we need some defense. a banshees should do the trick.

Pros:
Playing off your passive makes you a scary chick
You have an ult and range to protect you from most battles.
Carry status

Cons:
No longer really a support champion
Lots of gold to farm in a short ammount of time.
Doran's can only do so much for you for a while.

GLHF