As masteries , i take 21-9-0 , reason being is because corki is very squishy early game , so he can use those 6 magic resist , 2 armor and 2% dodge chance .
I mostly start off with a [doran's blade] or just [boots of speed] with 2 health potions and 1 mana potion . Depends on your team and the enemy team wich you'll take .
After buying [doran's blade] you'll go for the [berserker's greaves] , first buy the boots , after the [dagger]
GOTTA GO i'll finish this guide later (check again tomorrow)