Playing Kayle - it's all about striking a balance between her two strengths: damage and utility.

The recent buffs to Divine Blessing make leveling it early a GREAT option. Having a large mana pool to freecast Divine Blessing while doing respectable damage in teamfights makes Kayle a force to be reckoned with.

Pros:

+ Good damage early
+ Easy to farm
+ Good harassment
+ Very powerful ultimate
+ Scales well with AS/CDR
+ 3000+ mana pool with build

Cons:

- Useless without mana
- Mana problems before tear
- Righteous Fury pushes lane
- Top laner with no hard CC
- Annoyingly slow movement speed

Your basically start off with a Yorick/Urgot style build. You need to solve you mana problems to improve your laning and prepare for midgame.

Tear of the Goddess - Alot of your problems start to get solved here. You can start to be a lot less conservative once you get your tear. It's very possible to have your tear maxed out in 20-25 minutes as Kayle.

Manamune - Endgame, you will have a manapool in excess of 3000. The base damage along with the bonus damage will get you a total of 80 damage. The mana regen is great too. A super efficient and cheap item for Kayle.

Glacial Shroud - You're getting this item next for the CDR. Alot of people argue that a Stinger into Nashor's Tooth is a better choice, but I don't think so. The AP is ulitmately useless on Kayle. Getting more mana is more important for midgame. Your team should not be depending on you for damage.

Black Cleaver - AS, AD, and shred all in one. A great item to boost your damage.

Frozen Heart - This adds to your resilience to being focused as well as increases your utility in team fights. I personally believe this is the best CDR item for Kayle.

Zeal - More AS and MS are great for you.

Infinity Edge / Phantom Dancer - These items are basically your luxury items. If you are getting turbofed get your infinity edge and then your phantom dancer

Elixir of Brilliance - Get this any time after your frozen heart when you going to push down mid with your team. You now have 40% CDR.