First of all, I would like to apologize for my english (really not perfect).So I am not gold or something, but I've been playing this ninja a lot I hope you will be satisfied with things I'll write here, because it's not gonna be so much.I'll just write down the basics so let's begin.

Well you're maybe surprised by that 30/0/0 but it works.If your enemy is heavy AP/AD just get treads/tabi on your first back and potions.Remember, you can always roam.Bot will usually be warded but with a little effort, you can catch your enemies ofguard.You can replace AP quints with AD quints.

Well this is pretty much the usual.If you want to play her mostly max E first, get hextech, then sword of the occult and then go for AP stuff, because really, isn't your Q the most amazing thing on the rift?

You can play Akali as a jungler if you really wish so.It's not so hard you pretty much get the standart with only small changes in items.When farming, make sure you're using your q and then triggering it.It'll help you last hit since it does more dmg so you won't miss as many lasthits.Since her Q refunds energy if the mark triggers you can spam it for days.If the enemy is zoning you, stay under the tower and farm safely until you hit 6 and then kill/roam.

Pros :
Awesome in late game
Can escape easily with Twilight shroud
Can be played AP or AD
3charges on her ult
Cons :
CC screws her
Isn't really good in early game
To actually start doing something you need to reach lvl 6 first
Gets heavily focused

You should ALWAYS stay in behind until their team is busy focusing someone else.If you jump in first you're gonna get cc'd and killed immidiately.Come from behind and take down their ad carry and then follow up with their ap carry (if they switch focus to you run away to safety, wait, and then try again) everybody knows Akali is a beast, so everybody will be tryin to catch you, kill you.. you can't go solo or in their jungle with no way to get out.Their support will make sure to ward everything, so you can't just be running around in their jungle or alone in lane constantly dying.Team up with Shen, Rammus, whoever that has taunt our stun or knock ups.Shen can save you pretty easily if you just throw down W and he starts teleporting on you.He can also taunt enemies for a while so you'll have time to kill carries and squishies.

Champions with a lot of CC, champions that can reveal you.
Lee Sin is your biggest counter and if the enemy team has him he'll often swap lanes if he's not a jungler so you won't get a thing.Not every Lee Sin screws you, but the good ones are a pain.If you have Lee Sin against you roam or call for ganks.
LeBlanc I have a problem with 3/10 because of the high burst and silence.Early treads will help a lot.Also she can escape you with her W.

I hope you learned something new or something strange from a silver nab.I'll improve this guide with more experience I'll get and hopefully, this isn't so bad :X gl in yolo que.