Sell the shoes and get another BT if you think your damage are still too low. With this build and u active your E+R each time u kill an enemy champion, u can kill a lot of them one at a time, don't try to engage them all at the same time because they will focus you down. Let your team go in first and you will pick up a lot of kills later. Or you can backdoor and 1 or 2 enemy will come after you and you can kill them when u feel that they are alone. Make sure you have cleanse with you, it's very important because yi can get cc easily, and also try to get blue and red if you can first. If you think you died instantly if you engage any champion get a guardian angel instead of another Bloodthirster. Make sure to farm those BT first before engaging so they do more damage.

Master Yi is a champion of great gap closer, healing, damage and speed. He can be played either AD or AP. When played AD, he can be assassin, tanky damage dealer or offtank. I think its best to build him as assassin(pure damage) because you come out of no where and kill their squishy.

Pros
Great pusher/tower/farmer destroyer
Pretty easy to learn overall
Great escape/chase mechanism
CD resets/halves when you get a kill/assist(if Highlander active at that moment)


Cons
Vulnerable to disables like blind, stun, suppress, fear, etc
Low HP poll
squishy

As yi u can jungle very fast with this build or you can ganked the enemy team if you know where they are on the map. with 2 phantom dancer you are very fast and crit most of the time so they can't get away easily, get red it's important because of the slow and damage helps too.

Team with someone who can stun, you get so many kills that way. Never engage first unless your team have a zilean or kayle that will help you.