Hi, I'm A***ura, an Akali Jungle main, with around 350k mastery with her at the time of this post. Welcome to my Akali jungle guide, which will be improved and updated along the way. It's my first guide, so I hope you guys will give good suggestions on how to improve this. I will be assuming that you already know the basics of playing Akali, so I wont be going through how to do her combos (they aren't that hard).
You can watch my Akali jungle video here

EDIT: For some reason my summoner name is censored. I'm Aku.mura (remove the dot) Play Video

You are the Jungler. Flash and Smite is pretty much the only option.

Viable Marks
Attack Damage, Magic Pen, Hybrid Pen
Viable Seals
Armor, Health
Viable Glyphs
Ability power, Magic resist(vs heavy magic comp)
Viable Quints
Ability power

Both Flat and Scaling runes work, but I prefer Flat runes for a better early game

12/18/0 is also viable if you want, to get a bit more damage for even greater fragility.
Wanderer, Precision, Tough skin, and perseverance and posible alternative masteries.

Hextech Gunblade The quintessential Akali item. Gives AP, AD, burst damage, a slow, and omnivamp for healing between kills. Get this core item ASAP
Zhonya's Hourglass Gives armor, AP, CDR, and an amazing active that allows you to regenerate energy freely, refresh cooldowns, dive the enemy team far more safely, or all of the above. Great at countering burst and physical damage.
Abyssal Mask AP, CDR, magic resist and a large amount of magic penetration. Probably by far the best item against low magic resist mages.
Lich Bane Greatly increases offensive capability with AP, Movement speed, CDR, and a passive ability that amplifies damage of attacks. It will also let you absolutely demolish towers with sufficient AP.

Play Video