Hey, this is my first build that i have put up, so please try and be nice.
This is what I use as Master yi.
With this build you will be able to carry your team really well, once you get to your Black cleaver it is basically GG to you, you will be able to solo baron (i did this with red buff tho) and you should still be above half health just meditate to get the health back.
Please leave a comment try and make it constructive criticism,
Thank you.

Ok so my items look pretty odd, the reason why i get a long sword is with wuju style you can hit really hard, when you get around your Infinity Edge/Black Cleaver you can sell your long sword.

I really like Exhaust and Flash, Exhaust is really good early game when you don't have a lot of movement speed to slow them down and reduce their damage out put for a few seconds, Flash i love this spell i use it with most champions because 1: grate for chasing (Flash then Alpha Strike them) 2: awesome for getting away (Flash past walls)

Pros:
Awesome damage
Grate attack speed
Good life steal
Hits like a truck
Nice movement speed

Cons:
Will normally get focused
Can be squishy (but if you play smart e.g dodge skill shots you will be fine)

Farming early game isn't that good but mid and late game is really good.
Early game: you don't have much attack speed, but you have a lot of attack damage and can hit really hard so last hitting isn't that hard
Mid game: you have alright attack speed so they die pretty quickly also Alpha strike helps
Late game: Alpha strike into the middle, right click and sit back and watch your minion kills go up.

If you are laning against a range or some one with good harassment get up Meditate before Alpha strike or Wuju style if you want, but I really like the attack damage Wuju style gives you early game.