Kayle Is awesome. She is one of the most under rated champions in the game but has a huge damage output and has some of the highest base hp in the game. Her ult makes it so she can 1v1 just about anything. If Kayle gets fed its instant gg. This build is very simple in design and every easy to work. Its different then the normal straight ap build or straight tank build. It isn't meant to be tanky at all. It is also meant to have a strong dpsing capablity which it does.
So Please read through this guide and vote on how you feel I did on it after you try it. It always works for me.

Pros
She doesn't get target'd often
High damage output
High base hp
Strong q with slow
Amazing ult
heal
Good Movement speed

Cons
Has trouble with mana early game.
Melee
Has trouble with silence and stun

So in this build alot of damage comes from her magic damage so I try and max her magic damage with magic pen. Also the more cd reduction the better.

Kayle needs mana. Her first item helps but the masteries make it perfect unless you uber spam her abils.

I get the Meki Pendant first and 1 Hp Pot to start. Then the fiendish codex so the she has almost no mana problems all game. Then i get the cd boots to give her movement speed and make her ult come out faster. Then Rageblade so she can start dishing out huge damage. Then I get nashors tooth so she now should always have good attack speed and a constant ranged. Also her ult can come out every 36 seconds. Then I start with revolver and then build up to gunblade. I keep getting gunblades(Cause i can) till the build is full. If you get 3 gunblades you are unbeatable.

THIS IS NOT A SUPPORT BUILD
That being said I try and max out her q and get one early w to help carry myself in a lane longer. Then i max out w and finish with e with ults in between. So that part is pretty simple.

I always get clairvoyance and teleport so i dont lose a lane or get ganked. But if you like to spam more abils than most clarify is ok. Also flash is a great escape. Ghost works well with flash if u have trouble getting away.

Kayle is a good iniator with her q slowing someone then e doing big aoe damage. Once her teamates start coming in you should start to back up and let them go while helping them from behind. Figure out what teamate they are targeting and spam her heal on them. If someoen looks like they are going to die ult them. If you and ur teamate are goign to die leave them to die and save urself because this is not a support build.

well hope u like my build and hope u get to like kayle too. Please comment and vote.