This guide is still in progress and I will update it, comment and give me some suggestions and I will consider putting them in.

Master Yi is one of the very rare champions that have incredible amounts of potential and if you know how to put that potential to use then you will own lots of noobs.

The armor penetration runes are for easier kills and they will assist you while killing tankers like Shen, the critical strike runes will enable you to do more criticals and the last set of runes will boost the critical damage b a little but it's better than nothing.

The masteries will give you reduced damage from others and you have armor penetration, increased damage, and your exhaust spell is upgraded to level X.

The Berserker's Grieves give descent boosts for the price, after that you get Stark's Fervor because of the life steal and attack speed. Frozen Mallet is to not be squishy and you can slow down other champions with the slow passive. The Infinity's Edge will increase your DPS. Phantom Dancer is for the criticals and attack speed. Last but not least you have The Bloodthirster which will let you stay in lanes longer because you regenerate life faster than others can kill you.

If you are facing tankers like Shen, consider getting an armor penetration item such as the Last Whisperer.

You want to max out Alpha Strike and Wuju Style first because they will help you farm creeps and harass champions. The meditation comes last because by the time you get Stark's Fervor you can life steal to get health back pretty fast.

I would recommend ignite and exhaust because at the beginning of the game when your about to kill someone and Exhaust failed you and they have like one bar of health left, use Ignite and they should die. I did that once and it worked pretty well.

At the start your gonna want to last hit them because doing so gives you more exp and gp. You can even Alpha Strike them and they get weakened and thats when you last hit them, or you can be all lazy and let your minions do the work and then last hit them, but that's too slow and they could've leveled already.