Hey, this is my first build so any criticts are welcome.

Magic Pen reds, and then flat AP on the others - more AP, more early game burst.
You can replace the AP seals with Seals of Vitality for some extra HP.

9-21-0 | Works extremely well early game, had no problems with it.

Dorans Blade - acitvate your spell vamp passive,bonus health and some lifesteal.

Boots of Speed - some bonus movement speed to keep you either close to your enemy when chasing or moving back to your turret.

Sheen - first real item - and it's awesome - amazing synergy with your Q skill and gives an amazing burst that will make your enemies run when they see you.

Mercurys Treads - 25 tenacity, 2 movement speed - the tenacity is, in my opinion useful for escaping those AoE spells when you're in stealth.

Hextech Gunblade - an extra 25% spell vamp to your passive = 35% spell vamp. This keeps you alive during fights. You can buy this before sheen if you have trouble staying alive early on.

Rylais Crystal Sceptre -a must-have item for AP ninjas (well, akali and kennen) - gives HP and AP, plus a nice passive that slows down your target if, for instance you run out of ulti charges.

Lich Bane - AWESOME. It describes it perfectly. By now you have more AP then AD and combine that with the burst from your Q skill, which equals A NUKE.

Rabadons Deathcap - ****load of AP + an increase of your total AP - just a ****load of extra AP to boost your ulti and Q skill.

Hextech Gunblade - to finish off your hextech revolver, this gives extra AD to give an increase to your passive aswell as some lifesteal.

Zhonyas Hourglass - armor, extra AP and a passive for those focuses that will come your way in end game.

Now, for the skill sequence, the one Q and one W are a MUST.

Then it can go two ways: max out E for terrific farm, or max out Q for harrassing the enemy. Personally, I like to max out E cos the farm from it is just OP.

Flash - this is amazing to escape from your Twilight Shroud, juke in the jungle, or just gain plain distance when running away.

Ignite - good early game to finish that little bit of HP on your enemy that always stays there and wont go away.

Exhaust - you can take this instead of ignite if you have problems with keeping up with your target, but personally, I dont have a problem because your ulti is basically made for chasing.

Farming with Akali is EXTREMELY fun and as I see it there are 2 ways it can go:

- max out Q skill first and do the standard combo: Q-auto attack-E if necessery

-max out E skill first and try to get yourself in the middle of the minion wave (use your ulti in mid and late game for those big minion waves).