This is just my basic build for Kayle on Dominion. This is here to remind me as much as anything else (memory problems).

The armor penetration from the desolation marks is a good idea for pretty much any build.

The attack speed seals make Kayle's passive a little more effective, while letting you hit faster so you can make good use of the penetration and heavy late game damage.

The insight glyphs make sure you get the most out of Righteous Fury, because the magic splash damage penetrates better.

Ditto for the Quints ^^^^

I use 24-6-0 because utility just doesn't have any purpose in this build.

Now for the important part, items.

Sorcerer's Boots give you better speed to reach points faster, and more of that beautiful magic penetration.

Zeal pumps you with more attack speed, letting you spread out the splash damage effectively.

Last Whisper balances out your penetration while giving you more damage.

Hextech Revolver is a wonderful side effect of needing the Gunblade, it gives you a ton of AP that really boosts Reckoning.

The Tiamat is very similar to one of Kayle's abilities... and it makes it constant except for the range part.

The Hextech Gunblade... beautiful... ok, so this baby gives you AP, Damage, Spellvamp, Life Steal, and a ranged attack that combined with Reckoning can devastate a target before it has a chance to react.

The Sunfire Cape makes you less squishy, and helps to keep melee fighters at bay.

If you have enough money, finish off zeal with phantom dancer at any point, you could also just replace the gunblade with whatever you want.

I really don't care what summoner spells you choose, they are mostly personal preference, but I have found that promoting a minion at the right time can mean a really bad day for the other team. Surge can get in those last few hits to annihilate enemies. Exhaust is good for keeping people in range of your various attacks, and with that one mastery, it also weakens armor and magic resist.

BE. AGGRESSIVE. B-E AGGRESSIVE. One of the wonderful things of Dominion is that it is a small area with low respawn times, and feeding doesn't really mean anything because of the passive xp. Plus, Kayle has that wonderful ability that let's her become totally invincible for short periods of time. I mean, come on, that's just awesome. Timing Intervention just right can make you survive a gank, even if it's you attacking 3 players and not them attacking you.

This guide should allow you to completely annihilate. (Remember that dying doesn't matter, wait a few seconds and you can resume giving hell). Please leave comments if I wasn't clear on anything.