Hi everybody !
This is going to be my 1st guide.I really hope you enjoy this, because Kayle is one of my main top,adc and mid champ aswell:).
Well, I choose her ,because the most players play her full AP or support but I'll show that she can do more then support.She is dealing with the right equip and the right techniques insane damage and with her Intervention she can survive a teamfight or can towerdive pretty simple.

Pros: -she is one of the best tower divers ingame
-she has an awesome damage output on single targets and later on multi targets
-the enemy will rage you that you got luck,because of your ultimate
-you can help your own teammates not to die in a teamfight
-you can't get towerdived

Cons: -you are dependent on attack speed and some counters are Malphite or Lee Sin cause of the AS slow
-if you got in early no kills or atleast farm you need to farm the rest of the game to get op
-CC is pretty hard conter
-she havn't got an OP DANCE !!:)
-in early you can't farm so good, because of your Righteous Fury CD

For runes are flat runes pretty cool because they are supporting the early damage Kayle does good.The Greater Seal of Mana Regeneration runes are just for harrasment that you can do the Reckoning and then auto attacking with Righteous Fury combo.And why do I take Greater Mark of Attack Damage Damage and Greater Glyph of Ability Power and Greater Quintessence of Ability Power is simple.I take it like this, because you need AD for your early damage and the AP is for your amazing Reckoning damage. You will going to reap them with a bit training and this guid. :D

I take for masteries 26/0/4.The 4 points in utillity for mana regeneration and the CDR of Flash aswell.The 26 points for every offensive hybrid damage.Defense what is this ? You got ur Intervention and your Divine Blessing!So if you time that well, you will make every enemy rage like a boss that,because you got luck.BUT YOU DON'T HAVE LUCK!NO YOU HAVE THE SKILL!

The items are mostly for magic damage but in the end... it doesen't even matter... :). I mean in the end you will shred so much magic rasist that the enemy got about 40. And this to 3 targets!
Now comming to the explination why I take these items.
I take a Doran's Blade because it is in early the strongest item i suggest.And with the AD and health it's easy to kill someone.
After that I buy a Vampiric Scepter because you need the (low but still there) self heal in the laning phase.
Then I'am going for Berserker's Greaves because of the AS in the early game.
Right after I choose Stinger also for the AS and the CDR,also you can upgrade it into Nashor's Tooth which is pretty awesome because of the AS,CDR,mana regeneration and the AP what makes it to an optimal item for Kayle.
This is followed by a Guinsoo's Rageblade.Why I take this item? Well,if u got lower than 50% of your life the passive will activate and everyone tries to kill you.BUT,because of ur Intervention you will reap one or maybe two also in early to mid game.
Then I choose Runaan's Hurricane for the AOE damage comming from the Righteous Fury (because Runaan's Hurricane also applies on hit effects so it will do the same damage from the Righteous Fury spell also in AOE)for winning every teamfight! :)
Malady is my last item.Well you think why Malady and not Rabadon's Deathcap or Infinity Edge ?
I don't know maybe the additional magic damage and the magic resist shredding. I really don't know why I'am taking it.It just works fine :)

The skills are awesome for single traget burst damage.
In laning phase you land a Reckoning on the enemy and then you follow him with the Righteous Fury while you healed yourself with Divine Blessing for the movement speed boost to get more auto attacks on him.
If you go for an one vs one you need to be carefull.And try to do your Intervention when he does his or her.Or to avoid the most damage.And if you realise that you are going to loose try to Flash into a bush (just working when your opponent is melee) and do your Reckoning, Righteous Fury combo for massive damage.If u got your Intervention do it when he is getting next to you.About one second before the ultimate is running out you heal yourself with Divine Blessing and maybe get Ignite on him.So you can turn a fight from loosing to a winning or to an one for one exchange.

I recommend Flash and Ignite for her.
Why i take Flash: -you can get over walls
-you can Flash near an enemy for the Reckoning, Righteous Fury combo and finish him off
Why i take Ignite:-the true damage is pretty insane with your normal skill combo and i think(I'am really not sure about that) the Reckoning is also afflicting with Ignite.So your Ignite does more damage.
-it is better for finnishing someone off in a turret dive,because you can get earlyer out of the turret range but get the kill.
-you got a heal reduction of enemies which is pretty usefull at ad carries or a jungler like Warwick or Dr. Mundo

Kayle is really strong champion when she is played well and with the right items you can try a one vs 5(if the enemies don't got too much CC ---> perma stun) and you will finnish off atleast one or two enemies.
She can also safe the teammates from hard situations and help them to get a kill.

Well, team work... Help your team but don't forget to farm you will need it.Try to get not every kill if u are top or mid and try to get every kill when you are carry.You have a heal which is speeding someone up so use it for that aswell.Try to speed someone up who is chasing an enemy.
Your ultimate is your nearly strongest weapons so don't ult everyone and ty to give Intervention to someone who is nessesary for a teamfight or for the team(that means don't be such an ego and use it just for yourself NO use the Intervention for someone else).

Farming is sooooo easy with her in mid to late game, because you don't got the high (like in early with about 18 seconds)CD on your Righteous Fury which is dealing massive damage!In late game you got Runaan's Hurricane which is amazing with her Righteous Fury.You need just to do about 2-3 auto attacks and the wave is farmed.

BUT in early you just harras the enemy so that you can farm, because you got the respect of him!
BUT if you aren't going to win your lane tower farming is easy as well.And you will get him so or so in early game or in late game.In any time he will try to kill you and then you are going to kill them ,because of this insane guide (with really poor spelling and grammar I know and I'am sorry for this)
that will help you to kill everyone! So good luck and destroy them for me ! :D
Aswell iam sorry for that it's not looking that interesting but I think it will help you.