This Build/Guide will let you look at Akali in a new way, since akali is strong in Early thru mid game and just full nuke at Late game.

!WARNING! (read the whole guide before you use (or else you wont understand a thing) !WARNING!

Abbreviated Terms
AA = Auto-attack (Basic Attacks)
AD = Attack Damage
AP = Ability Power
AS = Attack Speed
AoE = Area of Effect
CC = Crowd Control (Stun, fear, slow, snare, etc)
CDR = Cooldown Reduction
DoT = Damage over Time
ELO = Elo rating (Rating system designed by Arpad Elo that is now used in gaming communities worldwide)
FB = First Blood
GP10 = Gold Per 10
HP = Health
LS = Life Steal
MD = Magic Damage
MP = Mana
MR = Magic Resistance
MS = Movement Speed
OOM = Out of Mana
SV = Spell Vamp
DPS = Damage Per Second; also: Strong Auto-attacker
MDPS = Magical Damage Per Second; also:Strong spells; casters
MP5 = Mana Regeneration per 5 seconds
HP5 = Health Regeneration per 5 seconds
ArPen = Armor Penetration
MPen = Magic Penetration

This guide contains 2 snowball items (Mejai's + Occult) ppl is going rage on me for this cuz most of them dont know what to do and when, once you get 20 stacks in both, NOTHING CAN STOP YOU. this guide/build is created cuz i didnt find any Akali ''pro'' builds when i was starting of with her.

Pros:
Akali is probably one of the best chasers in the game duo to her ultimate
Great Escape (Flash+Shadow Dance+Twilight Shroud)
Huge amount of damage thru whole game (Early/mid/late)

Cons:
Squisy at early game.
Often Focused in fights
Wasted all Energy + Stealth in CD and a gank is on your way = you are finished (Early Game ONLY !)

Twin Disciplines: This is what makes Akali sick with Hybrid items, since if you have these Runes + Masteries you are gona activate both of her buffs at lvl 1

Mark of the Assasin: The first spell (Q) that Akali has, its good for last hitting creeps at low lvl and does good amount of damage at lvl 1 and has 6 sec cooldown at rank 1.

Twilight Shroud: This is a get-away ability or Slow your opponent/s mix this up with your ulti and you got yourself a kill or mix it up with Flash and you are safe.

Crescent Slash: This is Akalis AoE ability and in mid/late game this is your best healing ability once you get low (go into large amount of creeps and just spam it until you get full health) but this spell is doing alot of damage aswell, so charging with her ultimate first and use this = epic !

Shadow Dance: This Ability is what makes Akali sick, with this ability, she can chase / run really easy, example you are low on hp and its early game you see the mid champ go bot (where you are, nuking their tower) and you cant make it to your tower, so you meet him/her up, put down your Stealth, ulti on him and use flash as a get-away to your tower = win !

You Should Specc like this:
Max out Q ---> E ---> W ( of course specc on your ulti every time you can )

How you should start at an 1v1 or 1v2: W near you then Q - Ulti - Auto-attack - E repeat = target dead, do the same thing agian and you won this fight :)(spam E as much as you can)

How you should start at an team-fight: stay back and let tank charge in first, here your job is to take out the squisy-ones first: Ulti - Q - Auto-attack - lay down W near every enemys + yourself then just nuke around with E and repeat Ulti - Q - Auto-attack (spam E as much as you can) if an champ runs away dont follow him/her until your team goes with you, cuz your ulti will last hit them if they come to the battle agian.

Flash: this is probably the best spell for anything.
you can get away saftly combined with Stealth + Ulti
or you can chase your target easy with ulti + flash (slow-sealth if needed)

Ignite: this thing is really imbah on akali early game, just think about it, once you lvl 6 you get your ulti, if you go mid or lane its an 100% kill = Q - Ulti - Twilight Shroud - Auto-attack - E and ( Q - Auto-attack if needed )

Ghost instead of flash works aswell, but its much easyier to get around with Flash, but ghost got better chase ability.

Exhaust is something i never take on Akali since she got her Slow (W)

Rest of the Summoner-spells i dont use (since Akali is pure nuke, but if you prefer to get heal instead of something or anything else its fine, (but dont ever take Rally,Clarity, since she is OP as she is, and Akali has Energy, not mana/rage etc.

Greater Glyph of Potency: 0.99 Ability Power (4 of those)

Greater Quint of Potency: 4.95 Ability Power (3 of those)

Greater Seal of Vitality: 19.44 Health (1.08 per level) ( 9 of those)

Greater Mark of Strength: 0.95 Attack Damage ( 7 of those)

Greater Mark of Alacrity: 1.7 Attack speed ( 2 of those)

Greater Glyph of Force: 3.06 Ability Power (0.17 per level) (5 of those)

These are the Runes i use on Akali, since both of her buffs activates and you get more health, and more chance of get 1st blood + later in game ---> mid/late game = if you got feed or atleast have 10 stacks in both Mejai's + Occult = you will be hard to be taken down.

This items is what i use on Akali.

Start off with buying Long Sword and 1x hp pot.
Once you get enough gold head back to base and buy Occult and regulare boots, and if your lane was going good and you got more gold to spend, then buy Amplifying Tome and build towards Mejai's Soulstealer. go to your lane agian and pwn until you get enough gold to buy Hextech Revolver (but first get your boots = Boots of Swiftness, so you can move around faster). look at map and see if there is any trouble (at this point you should be lvl 6 or higher) if you see mid or top/bot lane having trouble and needs a back-to-base go to their lane and tell them to go b, or if its going good for everyone you can go and get a gank easly. next item you should get is Rylai's Crystal Scepter, many have asked why i buy this and i reply: akali needs the 500 health from it, and the slow that she gets from this item is just awesome - there will be no escape for them. once you get this item, move around the map, push / gank as much as you can cuz the next item will be Hextech Gunblade. with its activate you can take out an 2v1 without getting damage much, even 3v1 if you got pretty feeded. from here you should output trouble to the other team, and its your job to take out the squisy one asap, since akali is like a spider (can move to every target in a team-fight as her ulti refresh for every kill/assist) so the choice is yours if you get targeted much you take Guardian Angel or if you are facing a bunch of AP team you take Banshee's Veil, or you just take pure damage and build your Lich Bane as your last item, you may ask why: Akali's Q is just like lich bane, and come to think of it, you start of with Q - ulti = your target should have like 40 - 60% hp left.

Item Summary:
Long Sword - Sword of Occult
Boots of Speed
Amplyifing Tome - Mejai's Soulstealer
Boots of Swiftness
Hextech Revolver
Rylai's Crystal Scepter
Hexttech Gunblade

Last Item:

Lich bane (damage output)
Banshee's Veil (AP defense, if they target you alot)
Guardian Angel (if you feel like you die much)

Late game with Akali: take down the squisy ones asap, move to the thouger one and last their tanks (if they have any)

Once you got all items, buy all pots

Elixir of Brilliance
Elixir of Fortitude
Elixir of Agility
+
Oracle's Elixir ( even if they dont have an stealth champion, buy it for the glow at the end of the game ;)

Got any questions or you think i made wrong somewhere, please tell me before voting.

Thank You, i aint finished with guide yet (1st guide but still got more to work on)