This is my first guide I know I haven't figured out how to do much of anything in terms of making it look prettier so let me know what you think in the comments.

I've started playing Kayle alot recently and came to realize I didn't find any of the other guides to be maximizing Kayle's full potential. I've also found that alot of other people playing Kayle seem to have no real idea what they should be doing.

I've tried the pure AD builds which are good but I find it makes her Divine Blessing feel a bit useless. I've also tried the hybrid builds where you seem to buy nothing but pure hybrid items such as Trinity Force and Guinsoo's Rageblade which are generally expensive and boost your damage very little compared to other items of similar cost. The on hit builds I simply find too boring to want to play, right click to win is a bit lame. And the AP build aside from just hitting ridiculously hard with Reckoning and then being relatively useless isn't particularly good for your team.

Pros:

Has amazing damage
Has a pretty decent heal which offers a nice movement speed boost to help either run away or chase down enemy champions
Can farm creep waves faster than most any champion in the game
Can support well even if under farmed/fed
Intervention is incredibly versatile and can easily change the outcome of any fight
Can escape ganks unscathed rather easily once she has her ult

Cons:

Needs cooldown reduction
Pretty squishy mid/late game
Needs farm/fed in order to be remotely useful as a carry
Can be difficult to master when to use Intervention

Following this guide all of the cons will be dealt with leaving you with only the positives.

The Marks and Glyphs are set up to provide you with the best starting damage possible, with the Seals making you less squishy end game, so you WILL BE FED by the time the laning phase is over.

I don't really suggest getting Armor pen or Magic pen runes because Kayle's passive Holy Fervor + Weapon Expertise + Arcane Knowledge will give you 25% Magic and Armor Pen and unless all you plan to do is focus down the tank (which is a terrible idea) you don't really need any more than that.

For summoner spells Flash is a must have for the other one well Exhaust and Ignite both work really well.
Others that you could get but I don't really recommend would be Clarity, Heal, and Smite

While I haven't tried any of the 2nd group Clarity could help you early game but would be useless after you get your catalyst the protector. Heal would work but isn't really necessary on Kayle unless you plan to have a bad early game or something and resort to only trying to support the rest of your team or you like to over extend alot and Reckoning, Intervention, Divine Blessing, and Flash somehow won't be enough to save you.

While I personally haven't tried jungling on Kayle I don't think she'd be bad at it at all. Her Righteous Fury could destroy jungle camps very quickly, and when ganking coming in with Divine Blessing to quickly approach the enemy and then hit them with Reckoning so they are slowed while also dealing massive damage and increasing any further damage you do to them works very well.

Like I said in the intro I've tried AD, AP, and the usual Hybrid builds and have found the one I came up with to work the best.

I like starting with the Doran's Blade over Doran's Ring because with your runes and masteries you should already have close to 30 AP and despite the 3% lifesteal being small it helps you stay in lane longer than using the ring.

You should aim for being able to buy Fiendish Codex and Boots on your first trip back, which will cost you 1595 gold but with Righteous Fury that shouldn't be too difficult for you to achieve.

Every game that I've made it to the Atma's Impaler I've had a 3.0 k/d or better at the end so I know it works (which has been every game I've played Kayle where we didn't have an AFK or someone with a score resembling 0/15/0).

As Kayle you could certainly use the AD, Crit, and Armor Atma's Impaler provides you. The only other items that can provide you with AD and Armor are Wriggle's Lantern and Madred's Bloodrazor neither of which I think do as good a job as Atma's Impaler and it does it at almost 1500 less gold than the Madred's. At level 18 you will have 2900+ health (closer to 3000)and with Atma's that is giving you 59 AD + 45 Armor + 18% Crit and no other item in the game can match those stats for the price.

In fact I've never even been able to build the Lich Bane but based off of how well the rest of the build works and the fact that you'll have over 300 AP and 250-270 AD at that point it couldn't possibly be a bad thing for you to get. You can go for whatever you want for last item though another good possibility is Rylai's Crystal Scepter. I'd just prefer Lich Bane for the MR, move speed, and much larger damage increase.

In most games you are covering the role of support to at least some extent, you have a 3 second invulnerability spell and a heal with movement speed boost people expect you to use them on more than just yourself and you are hurting your team if you don't use it on them.

When the tank is about to initiate it is almost always a good idea to cast Divine Blessing on them so that way they can successfully infiltrate the enemy team and possibly get to the squishy carries at the back so your team can take them out quickly.

Then there are more strategic things you can do that will require quick thinking such as is your team well organized and generally bullying the enemy in team fights? If so maybe you could cast Intervention on yourself and go in at the same time as your tank and start attacking their carries. If not wait for the enemy to fight back see who on your team is being focused and get Intervention on them before they get too low; this usually causes the enemy team to stop focusing them and go for your tank or start attacking at random which is exactly what you want to happen.

Always be on the lookout for those long range ults from champions like Ezreal, Ashe, Caitlyn, and Lux they are usually aiming for someone weak on your team make sure you got your ult ready for them and with only a ~45 second cooldown by end game it will be available to use more often than you'd think.

I hope you found this guide useful. It was my first guide I wasn't able to figure out how to do everything I wanted to with it, but hey I'd say it's not too bad and hopefully this will improve the quality of Kayle players we see in the League from this day forward.