Akali is an assassin who's main role is mid/top but can be a jungler in certain situations. Why should you pick Akali? Well, look at voyboys(Best Akali in the world) videos to see why. Quick tip ALWAYS BUILD HEXTECH GUN BLADE unless your feeding and your up against an MD champion such as Diana or Ekko.

Akali's Skill sequence will only change if your lane opponent is building early magic resist. In this case max your e first but in most circumstances just max your q

As i said always get hex tech revolver on your first back than build towards hextech gunblade unless your laneing agaisnt a MD champ and hes crushing you in this case build abyssal sceptre
just saying if your building jg Same thing with stalkers blade than build hextech gunblade than runic echos stalkers

When akali Mid or even top once you get 100 cs or just want to start roaming this is how you get fed and carry.

Combo's
When in lane Q wait until q is on 1 sec cool down than ult as your in mid air Use your hextech gunblade. W Auto attack q e auto they ded if not repeat the process. If low go into your smoke
and hide and kill them slowly

Escapes
USe your W to get away Duke them out stay in your w wait till they go past go out other way.
Ult to minions. If under tower of trying to get out of a tricky situantion Just ult to the passing wave than run away

You can and should use your Q to Farm if your laning against a marksman so they cant poke you.