Good start to explain how Akali becomes a major threat to all enemies, their skills are made so that the target can not escape and brings a quick death because we can perform a combo with them.
The first skill besides causing damage makes the next attack is stronger and more effective. His second ability makes her stay invisible enemies besides letting slow. On Tuesday, the same as a damage area, small space around him but with a high damage and a low recharge time. At its ultimate, allows it to move up close to the enemy causing high damage and allowing the use of all other skills. In summary, the Akali killer is a very nice and quickly wins gold which allows you to buy various items.
Let your build.!

To be able to explain the construction of its items will have to explain his first skill:

Twin Disciplines - Upon Obtaining Ability Power 20, Akali's basic attacks deal 10% bonus magic damage, Increasing by 1% for EVERY 5 Ability Gained Power thereafter.

Upon Obtaining 10 Bonus Attack Damage, 10% Spell Gains Akali Vamp, Increasing by an additional 1% for EVERY 5 Attack Bonus Damage Gained thereafter.

So I usually assemble a hybrid build where I base damage of a normal attack with your AP.

For most items that provide AP and AS with a bonus attack in the next physical attack.
With your skills it will inflict much damage beyond that whenever you use your ult, permitted a physical attack with high damage.
Everything else is only able to use the combo (I use the first skill, then your ultimate, once the third and soon after a physical assault followed by his second skill)

Good luck with the items and the gameplay.

Well right after the explanation of the items came to the runes and masteries.

Masteries: How the Akali and a hero of high damage, put most of their skill in Offense to further increase the damage and thus providing a more rapid death to the enemy.
Basically this is the masteries, I usually put a point in ghost walk to the middle of battle to leave no escape and run away if necessary we can move faster.

Runes: Practically increase the damage of your skills and your physical attack, so necessary to merge the magic penetration with the increase of Ap and the armor penetration.
In Runes seal, increase the hp a bit so Akali not die in battle very easy.

I hope I'm helping the guys!

Well of all the heroes of this game the more I liked and what most excited to play and Akal, because in every game she has a high number of murders and love the combo.
For many it can be a hero weak since it has low health, armor and magic resistance, but the damage makes up for his weakness. In the game heroes to carry more than her but the way you play with your combos and great.
Hope this helps, it's not a hero and very difficult to play but also not very easy because it requires a little dexterity and agility in their attacks and combos in addition to knowing when to flee.

Good luck and good game, and do not forget to comment and vote!