Runaan's Hurricane: This item is very useful. You would be stronger in 1v1s with a Phantom dancer or with a Statik, but this item helps you to survive teamfights, chase enemys. This item works pretty well with your passive. You will deal triple dmg, which means you will get more kills and 'cause of the kills you will get a lot of moovement speed.

Quicksilver Slash: You aren't an adc like Vayne. For example if a Jax jump on you, or a Lux sends her Q to you you can't jump out of that fast. This item will do her job. Thanks to your passive and your flash, after you activate this you will have enough time to get back to your position and continue the enemy hunt.

Guardian Angel: Buy this item in the mid-late game. 50s deathtime is sucks. You can do a lot for your team victory. Don't die 'cause you missed something.

Quicksilver Slash: It helps you to survive teamfights. If the enemy can put their focus on you this item will help you to survive a stun or remove a slow and get back to position and stun them to a wall.

Phantom Dancer: This beauty is my favorite adc item. It helps you to stay in combat gives you a lot of attack speed and crit chance. This item makes the teamfight easier as ****. JUST BUY IT!

Infinity Edge: You can ask me 'Why should I buy Infinity for the first item? I think I'll need attackspeed first.' If you buy an attackspeed item and you have only one B.F. Sword you won't have enought damage. The Infinity will helps you to poke the enemy hard. Thanks to your big attack range.

Statikk Shiv: You are a really strong Spliter. Use it for easier wave clear.

Edge of Night: If you want to stay more time in the middle of the teamfight this item is for you.

Boots of Mobility: If you need to split these boots are good for you. You can run from the enemy and you can get back to the team dope fast.

Ionian Boots of Lucidity: If you want to poke and just 'E attack Q attack E attack...'