I build Yi this way for tower taking and some pretty good 2v1 (against you).

You will be selling your boots.

The Guardian angel part of the build is where it takes some thought as it is game dependent; which takes you to 4 options.

OPTION 1 (If they have armor 150+ does not include tank) Build a last whisper
OPTION 2 (If they have armor 0-150 does not include tank) build a Black Cleaver
OPTION 3 (If you need more attack damage does not include damage against tank) Build a bloodthirster
OPTION 4 (If you're going well and not dieing) Build a Guardian angel

Probably your best bet at low level harrement is your Q so you wanna start with that.

Yi is a pretty easy champion to handle so you won't have to worry about needing to be skillful.

I recommend checking you cooldown on your Q compared to your fight length and the enemy ADC. More or less you're going to be keeping your Q at the ready for a large AOE or to avoid a basic attack or two in a duel.

The runes i've picked out on Yi are not needed any kind of AD would work, these are just the best you could probably use.