Yi can engage once his AP is high enough. Otherwise poke with him and engage when the tank engages.
Open with Alpha Strike, then Wuju Style, if you start to take damage then use meditate.
Yi’s main power is his CD reset when he kills someone with Highlander. Use Highlander and try and finish off champions with Alpha Strike.
Use Alpha Strike immediately if your CD resets.
Start with 2x Alpha Strike, 1x Meditate
Then get one in Wuju Style then max Alpha Strike then Meditate.
Obviously get Highlander whenever available.