Master Yi Build
Not Updated For Current Season
For 3v3 specificially, that is where I have found the best results with thi
This is from my own experience, but you can take this build however you like.
I always like to go for boots of speed and x2 health potions in the beginning, of the round and go down to the bottom lane of the twisted tree line to get the bottom gank with your team. It is crucial to get 1-2 ganks in the beginning, however it doesnt hurt to grab the 3rd guy to ace it up.
I prefer setting up the bottom lane on one of the higher bushes rather than the lower one, for a good ss position just in case if they retreat.
Experiment, its what got me the most success :]