Ok BC is not the best option and Lich Bane is better you right :) thx vor the comment

Ditch the boots of swiftness, and black cleaver. Get Spell pen or Murc Treds depending on the enemy team, replace BC with Lich Bane, far better with Akali then BC is. If you're doing very well early on get a SS instead of a Void Staff if you're confident you can sustain the stacks.

Edit: also get spell pen marks as they are far more important then attack speed and damage, and Ability Power over time has a large difference late game and is far superior late game as well.