Not Updated For Current Season
The masteries shown here are not yet updated for the current season, the guide author needs to set up the new masteries. As such, they will be different than the masteries you see in-game.
Lanning in mid
In your laning phase you will be last hitting with Q, and going in for E if your lane opponent walks too far from creeps. Because of your lacking defensive in midlane wait for 6 before going for pokes.
Lanning in toplane
In the toplane you can play more aggresive, you can hide in the brush and force your opponent to stay back because of them probably being melee, and your huge damage on Q, E combo. When you reach lvl 6 you can begin shoving your lane and take that turret. Just keep warded so the jungler doesn't join the lane.
In teamfights you are gonna focus the adc always. When you can get to them you just go in with R, Q, E and then throw W. Then wait for your team to join or the enemies to seperate, then pounce to the next one. And keep going at them until they die.
Use Q on stronger minions and monster and the use E to execute and shove through a lot of minions/monsters. You also don't need blue so that makes junglers like Amumu who really need blue buff funktion better. Think about this if your on a team with Amumu and your up against your counterpart. You can sacrifice yourself a bit since Akali can be played extremely defenisve and still get a lot of farm and kills. And maybe that Amumu will reward your team with easy teamfights.